I don't think even you understand what you just said.

Consumer devices are notorious for their reliability problems. Compared to a full blown server that you have 100% control over with almost insane amounts of RAM & CPU power & a lot of guarantees.

Running a migrations on a server is far, far different to running it on every users' device. The sheer scale of it is different.

> Using 4 GB per user on your backend works?

That was a comment on the average RAM on a consumer device - not the total RAM required per user.