For one proxy on one logged in account, sticky is the call. A persistent account needs to read as a real person on a stable home connection, so the IP has to stay consistent from session to session. A real user doesn't jump to a new IP every request or every login, so rotating under a kept account is the pattern that gets flagged, since the account looks like it's teleporting.
Rotation earns its keep on stateless work: scraping, mass creation, one off requests where a fresh exit each time is the point and there's no identity to protect. That's a different job from what you're describing.
For a kept account, run the longest sticky window your provider offers, or better, a dedicated static residential or ISP IP that stays yours, and keep each account glued to its own IP. If a session drops, try to reclaim the same IP, or at least the same subnet, ISP, city, and timezone. Match the device timezone and locale to the IP too.
Best,
Floqal