As I mentioned, would it be game breaking and make a single character into an unkillable solo machine by allowing temporary hp to stack? Assuming level 4 (max for this early access) Rally 12 (superiority die + cha mod of +4) + Aid 5 +Arcane Ward 12 (2x char level + int mod of +4) = 29 temp hp.

At level 20 that may be around 87 (depending on how aid works with the "every spell level past 2"). At level 20 most characters have around 200-230ish hp? How much damage do most encounters dish out per a turn? Would 87 temp hp make it where no one could get to the real hp?

My question is, does stacking make it so broken that the real hp pool never gets touched, or would stacking provide a buffer to survive 1 or 2 extra hits (if you have too many bad rolls in a row, this could save you from being downed, versus it doesn't matter if you have bad rolls, you will do more damage than they can do to you before your temp hp is gone)

I understand the want for this to be a purist version of 5e d&d or as close as possible to the game that a lot of you love bg1&2, but there are compromises being made already due to differences in table top versus computer game as well as ruleset changes over the years from bg1&2 and advancements in game development/technology. Also this is using larian's engine that already has deviations from the ruleset.

The original request was simply trying to create build diversity and interesting ways to play, but it is understandable if that build would be too OP as it grew, as I don't know all the sources of temp hp available and how they stack.

I, however, don't believe in not researching or trying new things because someone made a rule somewhere that said it always has to be done one way. Otherwise there is never room for growth and change and we will always have the same thing and same experiences over and over, but maybe thats what people want.