It works, with one real constraint, and the constraint is not the phone.
The constraint is that some actions on some platforms are simply not available from the web client, and if your account never performs any of them it has a shape that no amount of scrolling fixes. Depends entirely which platform — on two of the big ones the web client can do essentially everything and browser-only warming is indistinguishable. On one of them the mobile-only actions are the ones the account is judged on, and there you'll hit a ceiling.
What I'd run for 25 accounts with a laptop:
- Separate browser profile per account, separate proxy, and be strict about it — this is the part that actually matters and it's free. 2) Ten to fifteen minutes per account per day for the first two weeks, and do not distribute them evenly across the day, because nobody uses these things every four hours. Two clusters, one morning one evening, some days skipped. 3) Consume before you produce. Scroll, watch, follow a handful of large accounts nobody would question. First post no earlier than day 10.
The reason people buy phones isn't that browsers don't work. It's that 25 accounts at 12 minutes a day is five hours, and at some point you either automate it or you stop scaling.