I was critical of how healing worked as an 8 year old in 1981. So, I started experimenting.
% of max hp healing. No combat healing. Only temp hps. Etc...
None of it worked. Nothing felt right ... so I changed how I felt by reframing what wounds and hps are.
In my game, hps are your toughness. When you lose hps, unless it is your last, all you're doing is taxing your toughness through superficial wounds, 'exhaustion (not the game mechanic), and pain. If a dragon breathes fire on your PC and does 92 of 108 hps, your PC threw themselves on the floor and directed the blast away somehowm getting singed - but not wounded.
Thus, healing can be restoring your toughness by giving you emotional strength to endure more. This works for Divine healing, Marital healing, Arcane healing, etc...
When I made that mental switch, the entire hp structure makes a heck of a lot more sense. It also allows you to introduce a wound system as well that is separate from hp loss, and that can add a lot to a game (although I elect not to use it).