Here is the Herculean Wrestler as it was on the other forum. Although imo going fighter 5-> bard is much more versatile while losing almost nothing, if you want I can do a quick rundown of how I would build it.
Starting Race: Human or Mountain Dwarf
Human gives you a bonus feat at level 1, which you can use to get any number of awesome feats for the class. Dwarf gives you better stats.
Ability Scores: Here's your 27 point buy array assuming shameless optimization choices.
Str: 15 (Human +1 or Dwarf +2 - You want this maxed as soon as you can)
Dex 13 (Human or Dwarf - Full Plate doesn't mesh with Dexterity)
Con 13 (Human +1 or Dwarf +2 - See Strength)
Int 13 (Can't totally dump this because we need the Wizard multiclass)
Wis 10 (Fear effects are often wisdom-based. Don't totally dump this, despite how tempting it may be)
Cha 9 (Dump it - Cha saves are few and far between)
Fighter 1
Human Feat: Tavern Brawler
The build starts off in Fighter for Heavy Armor and Con-save proficiency, both of which are important later on. If you are a Human, get Tavern Brawler right away; it's nuts with the maneuvers you get starting at level 3. Note that this build is not going to get advantage on its grapple checks until level 8. It will make up for that with more attacks and more versatility in the interim.
Fighter 2
Fighter 3
As a Human, You really start to come online at level 3. Dwarves will need to wait a level. Now you can make a Trip Attack with one action, and then grapple as a bonus action with Tavern Brawler. Or Disarm as an attack, grapple as a bonus action, and then drag them away from the weapon as a move action.
Fighter 4
Level 4 Feat: Tavern Brawler (Dwarf) or Mobile (Human)
Dwarves will hit 18 Strength at this point and get to trip/disarm and grapple. Humans will get better move speed. Either way, this really opens up the battlefield for your class.
Fighter 5
This is the first level where you will feel unfair. All that stuff you were doing at level 3 or 4? Now you can double it with Extra Attack. Or quadruple it (...wut) with Action Surge.
Fighter 5 / Wizard 1
The build now switches to Wizard for two reasons. For one, you are going to start fighting larger monsters, and you need to bulk up in size category to handle that (don't count on Grappler until it gets erratad). Two, you need to start getting advantage on your Grapple rolls, or stronger monsters will outclass you. Three, you need some more utility on the battlefield, and survivability against scarier attackers. The Wizard dip will handle all of that and more. Spells to pick up here include Longstrider, False Life (which will offset your crappy HD), and Shield (massive spikes to AC on command).
Fighter 5 / Wizard 2
Fighter 5 / Wizard 3
This is the second level where you will feel unfair. Now you get to do everything you were doing before, but you are size Large, you deal an additional +1d4 damage on everything, and you have advantage on all your grapple/shove rolls. Enlarge will be your default concentration spell in most situations, if for no other reason than that it lets you grab bigger creatures.
Fighter 6 / Wizard 3
Level 6 Feat: Warcaster
Now that you are concentrating on spells, you need to get Warcaster to reliably make that save against higher damage monsters. The other Warcaster modes aren't useless and will give you added flexibility to your combat routine.
Fighter 6 / Wizard 3 / Rogue 1
We get Expertise and Sneak Attack here to keep up with the bad guys, adding damage and extra points to our ability checks.
Fighter 6 / Wizard 3 / Rogue 2
You don't actually need Cunning Action here, but I think this build is all about versatility anyway, and Cunning Action gives you a lot of options.
Starting at level 12, there are a few directions you can go with the build. You might want to keep going up in Wizard to pick up stuff like Haste (a solid competitor with Enlarge), or get some of those dex-based save spells for use with Grappler (in which case, you should get that feat at level 4 as a Human). Alternately, you could just dive into Fighter and take that all the way to level 11 to get your third attack, and then branch off for the last few levels depending on how the campaign is going. Or if you are enjoying the damage aspects of Rogue, you can pursue a Sneak Attack build instead. By level 11, you aren't super committed to one style of grappling, so you have a lot of flexibility in where you build from there.
If you go the Fighter route, you will get at least 2 more feats, which further add to your flexibility. Grab Shield Master if you don't mind single target grappling. Take Mage Slayer if you find that bullying spellcasters is your thing. Pick up Crossbow Expert if you want to use more ranged attack rolls (spell ones, likely). Versatility is the aim of this build, and these extra feats let you take your character in whatever direction you want.
Another nice feature of the build is that it scales really well with magical items. Builds like Grizzlyman and BJJ Master have a lot of item restrictions in what they can use. But your Herculean Wrestler? He can use armor, he can use magical wondrous items, he can use Wizard items, etc. He can even use weapons if you don't mind only grappling one target at a time!