Any recommendation for “Loot progression” games, but solo focused? (Ex. Warframe, Deep Rock, most MMOs)

I really like the gameplay loop of games like these kinds of games. Go on mission, get loot and crafting materials, use that to gear up for harder missions that grant better loot and crafting materials, rinse and repeat.

It's a chill vibe and I like the loop, my only problem is that most of these games either fall off in solo-ability or they are just designed for multiplayer groups. Does anyone have anything that does this that's made for solo? I think I'd say RuneScape scratches this and itch for me and is also soloable.