Thanks for the reply, i have made these changes (and i had to add login_maximum_inactive_lifetime_days , it was not in my grafana.ini).
so now the related settings look like this
login_maximum_inactive_lifetime_duration = 6M
login_maximum_inactive_lifetime_days = 90d
login_maximum_lifetime_duration = 90d
token_rotation_interval_minutes = 120
i then restarted grafana, and will update this thread with results.