Same. 2021 Macbook Pro w/ M1 Max chip; ARM chips seem to be common. Latest stable version of Opera. Does not remember any logins, sessions get cleared after short period of time or when closing. Even Opera Sync.
Hoping devs or someone at least acknowledge or give some timeframe, with this number of reports for almost 3 weeks. Was looking to switch back after getting a new laptop but the browser is unusable with these issues.