Two gold standard examples would be Azur Lane and Girls’ Frontline (the first one).

AL is pretty much a unit collection game with revenue coming from skins so getting all the units and gearing them up is pretty simple (or at least used to be, I haven’t played in a while). The bigger problem here is expanding your base capacity fast enough to have space for them.

GFL is kind of similar on that front - you get some units from playing the campaign, some can be farmed by clearing levels (including auto-clear after perfecting a stage) and the rest are pulled via production system, using normal game resources rather than gacha tokens. While said resources are also used for equipment production, upgrades and deploying your units while playing, it’s very easy to pretty much stay at a resource cap once you get the ball rolling (resources recharge automatically and can be auto farmed by sending teams on logistics missions).

There’s also Bang Dream - a rhythm game with gacha pulls for band members. Earning pull currency is pretty easy, just don’t expect to have every unit in the game. There were some money-sink changes that came with a big anniversary event last year (?) but they shouldn’t affect you much if you aren’t interested in fighting for top ranking spots during events (these are pretty much for mega-whales with no life beyond grinding). This one has a paid offline version for Switch, which forgoes microtransactions for pulling with tickets gained by playing and reading the story.