So not being familiar with Pathfinder 2e, I had to look up the Resting rule and I do like that. Depending on how many dice are in the Shield Pool, this might be a better solution then using the stuff from the 5e DMG.
The 5e DMG does have some suggestions for Variant Healing that I also like and will most likely use.
Slow Natural Healing
Characters don’t regain hit points at the end of a long rest. Instead, a character can spend Hit Dice to heal at the end of a long rest, just as with a short rest.
This optional rule prolongs the amount of time that characters need to recover from their wounds without the benefits of magical healing and works well for grittier, more realistic campaigns.
Healer’s Kit Dependency
A character can’t spend any Hit Dice after finishing a short rest until someone expends one use of a healer’s kit to bandage and treat the character’s wounds.
That could make the setting interesting as well, definitely grittier, not to mention the energy shield is almost a necessity then! Kind of like in Dune :)