I think part of the problem lies with framing of what's going on with the springing of an ambush or a surprise attack.
If you win the roll....and you still have to go in order of the roll....so no opening the door, blasting fireball, and then charging in if the order isn't that.
If executing this kind of plan is what you were hoping for, you were probably already screwed with individual initiative because you were counting on someone opening the door having the highest initiative, followed by the lobbing of the fireball, then the people charging in... And that's already problematic if your wizard had a lower initiative than the PCs who want to charge in.
Maybe it's better to consider initiative starting with the opening of the door. Then you don't even have to charge one of the attacking PCs with the cost of opening the door. The surprising PCs effectively get that for free. You could still have issues with the initiative order between the fireballing wizard and charging PCs but that's what Readying actions is for.
Party A is hidden with stealth DCs higher than party B's passive perception. Party A launches a surprise attack.
ROLL INITIATIVE
But someone from Party B still wins initiative (let's call them Sir Speedy). What do they see?
Is Party A's stealth broken because they made an attack, and thus the rolls are informing the fiction and Sir Speedy of Party B noticed the ambush just before it was launched?
Or does Sir Speedy get their turn but party A is still invisible and thus Sir Speedy doesn't have anything to do except maybe dodge or make an active Search check?
If you aren't considering that the attack is launched until the first ambushing PC actually declares their action, yeah, you kind of end up having to kludge this. But, if you consider everyone on the ambushing side effectively starting at the same time and initiative determining the
resolution order, then it's not so bad. The ambushers start moving to launch their attacks, starting the encounter, but Sir Speedy managed to react instinctively fast enough to get involved before any of the attacker attacks could actually be resolved.
Starting an encounter can be tricky when perceptions are unequal. I figure that's why various iterations of surprise rules have existed including only getting partial actions in 3e, the wacky variations in AD&D, the 5e.2014 variation, and now this. The trick, I think, is to frame it in a way that it gives you the cinematic results you want while retaining the uncertainty of D&D's game resolution tools.