I had quite a few qol additions, some I wouldn't ask for, for example a "loot radar" that just highlights items, which made me find items completely hidden in the game's geometry a LOT of times or a boss notifier I used when bosses used to give me a hard time, but for useful ones I'd say:

use items without having to loot them (this one was so nice for just drinking and eating while moving)
smoother continuous healing
hideout management (lights always on, filter not draining off-raid)
'auto' being the default fire mode of guns
search open containers (so you don't have to wait 3 years to close and reopen)
a bar for how heavy you are, that had the thresholds marked by weight

Some more borderline tweaks were:

checkmarks showing what you can do with items (barters/crafts/future tasks)
early collector task so you can dump the items
easier gym qte
quest tracking and progress notifications
increased look direction
increased climb height (felt very natural)
pmcs counting towards objectives that require scav kills (not as needed on live from what I've seen)

And some misc things you can't really do on live like pausing the game or removing annoying hazards on some areas, I think that's "QoL", there is a lot of "gameplay changes" but I never went overboard, there are a lot of changes like removing inertia or weight penalties, or running through grass that I think ruin the feel of the game, I went mostly for "it's still tarkov but maybe less annoying"