The 5e rules should be respected : they are not arbitrary. They are the result of countless years of game design and playtesting.
There exist ...
a) Temporary Hit Points. Ex.: Rally maneuver from the Battlemaster.
b) extra Hit Points which are not the same thing. Ex.: Aid spell.
c) some bonus damage soaking effects that are beyond the first two categories. Ex.: Arcane Ward from the Abjurer Wizard (that Larian butchered for some reason).
Though these categories never stack with themselves (eg.: you use the highest Temporary HP bonus you got), each separate category do add up side by side.
Example : you can have 8 HP from Rally (Temporary HP), +5 from Aid (extra) and an Arcane Ward (a shield with its own HP).
Last edited by Baraz; 17/10/20 06:00 PM.