Let's talk this out a bit.
To get the 6th level spell slot to cast that Spirit Guardians for 6d8, you need to be 14th level with this build. You'll get that one Spirit Guardians for your single 6th level slot.
To set this up, unless you have ample time to cast spells before combat, you're going to spend round 1 casting spirit guardians.
Then, on Rd 2, you're going to be in melee with 2 enemies and cast command on 2 of them to force them to flee. You want to use a reaction to take an OA on one and use BB (warcaster allows this), and use your bonus action to cast BB on the other using quickened spell. That is problematic as there is no rule that allows you to interrupt an action or reaction unless there is a trigger that allows you to do so (). You could cast BB on one of those targets using your action and then quicken the command, but if they make the save, they will not flee and you'll only get the weapon damage plus 2d8 from the blooming blade, if you hit with the attack.
They need to fail 4 saving throws and you need to hit with 2 attacks to do the maximum damage, and that damage is going to be weapon + strength + 11d8 each, or about 58 each. The minimum damage, if you miss on your attack roll and they make their SG save is going to be about 13 damage each. You've spent a 6th level and 2nd level slot, as well as 2 spell points and relies upon a lot of rolls.
While this is fine, it is not revolutionary and is going to be harder to pull off.
yea i corrected the post before your reply, its 5d8 from SG, but it get 6d8 at lv 13 not 14, as i said this is a 2 hexblade/X divine soul sorcerer (DS/HB/DS/DS/DS/DS/HB/DS...)
Action economy is
1) spirit guardian or precast it when its possible
2) BB attack and choose what to do with bonus action: quicken other BB or grasp of hadar for bring someone else in SG area, or use telekinetic for make the guy you hitted trigger the additional damage from BB if he want to attack in his turn (this let you save resources), or even use healing word, but from lv 9 it will always be quicken guardian of faith.
3) start with bonus action BB attack, than if you hit cast command (2nd lv) and order to the target you hit and to other target to flee. The first one gonna trigger BB additional damage as you already hitted him, the second one gonna provoke an OA (hopefully non only from my character) and gonna again get the additional damage as he cant stop to move, if you miss with the first attack you not gonna use command with your action but whatever else.
4) if there is a turn 4 will be probably for eldricht blast and grasp of hadar, for apply what guardian of faith still have to give and SG as well.
5) if there is a turn 5 he can probably heal himself and kill what is still alive just keeping concentrated on SG.
He dont have his reaction for shield and absorb elements only in turn 3, or anway whenever he choose to cast command for the OA and double full BB damage.
So, there is no bonus action interrupting my attack or reaction action (there isnt even an attack action and my reaction happens after command, not after the bonus action attack).
im not searching for something revolutionary, just a good way to make work SG with BB, without spending all my actions dodging. But yea, we cant negate that the DPR go from 26 to 118 (+13/25 for every creature above the second in the SG area), as for a fighter go from 0 to 120/130, with 6 hit roll if he use action surge (at -5 to hit, while this character hit without any minus, and kinda same for mostly of characters go from 0 till something less than 100 with 3 or more hit/saves, with mostly of the higher in DPR having a -5 to hit) but also true that the fighter dont have to care about spell slots and can still grow some DPR searching for OA via PAM or sentinel or via superiority dice, have more hp but of course less spells utility and less AC. I find this build very strategic compared with a pure fighter and i dont think there are so many builds with a so big AC and a so good DPR even talking in general (i neither considered the +proficiency to damage and 19/20 to crit on cursed target that its anyway a boost to damage), maybe a sorcadin do it even better (Pala/sorc/sorc/sorc/sorc/sorc/pala/pala/pala/pala/pala/sorc...) adding smite and a second attack plus the aura for TS, but it can end his resources probably too quick, a straight warlock with eldrich blast or hexblade probably is some less DPR, but anyway for sure less AC, as he must give up shield and hit with -5, or give up also medium armors and so be played ranged without tank, an evoker can deal probably more damage but again it cant tank, a paladin with 2 attacks can deal lots of damage via smite and some concentration spell but its neither near 100 unless again, giving up the shield and hit with -5. What i mean is: about DPR and AC this character dont seem the poorest of choices, even he have to choose every turn if have a reaction attack or save his reaction for shield spell, and this gonna depend mostly from the number of enemies he is facing i suppose (considering that anyway he have a +1 AC if compared to any heavy armored guy without shield, while if they wear a shield their DPR go a lot down normally without GWM/shapeshooter), but his DPR and defenses seem far from be a suboptimal choice, indeed bcs the DPR depends from many sources.
PS i forget to say, later on when it get 4th lv spells (so at lv 11 chaacter again) after SG in the first turn, in the second turn it will always cast bonus action guardian of faith quickened for 10/20 damage more to everyone around every round, making the SG area still more hot + BB or eldricht blast as usual action). Of course it can use less resources, but in my games normally we get 2 or 3 encounters a day, for sure no more, sometimes even 1 (but i dubt anyway that so many tables gets the 6 encounter per day as in the PHB exemple), so im not so worried about save resources because what he have seem more than enough. Esecially slots: 1st lv spells are for shield and absorb elements, or sorcery points, 2nd lv is for command (he can use command 2 times and eventually use the other slot for sorcery points), 3rd lv are for upcast healing and cure and maybe one more command if it dont need heal that much, 4th lv guardian of faith (only in one fight, or even dont cast it if there are 3 fights, for cast spirit guardians a third time), spirit guardians and upcasted aid, 5th lv spirit guardian. it seem work kinda well to me till 2/3 fights a day, for more fights its probably necessary to save resources but well, i supose everyone does for more than 3 fights a day except maybe the fighter, and its anyway kinda sure that the more encounters a day there are, the more the classes with short rest resource's recovery shine.
