First, there's no such thing as an "actual" mmo on mobile due to the limitations of the control scheme.
Second, mmos ARE gacha. Gacha is no different from grinding some boss for a 0.6% chance drop, daily bullshit and other artificial timegates were all spawned in MMOS. The only difference is that mmos have a community to distract you from how predatory they are, gacha games are just the predatory aspects, and any community outside of the game are just a bunch of gambling addicts roleplaying as entrepreneurs, stock brokers, etc. Rather than distract, they exist to encourage.