-on "Connection Tracking", TCP Established Time-out change from 1d to 01:00:00
-pls do not using many rules on mangle, nat, and/or filter
-pls do not activate modules on Mikrotik RouterOS you do not needed it
also run check-installation to see whether some component has been damaged. it is not very likely but freak accidents happen. if something is damaged then just "downgrade" to the same version which reinstalls the files.
as an example i've had the snmp module crashing on me due to data corruption (bad flash) and it will then (afaict) restart the snmp module endlessly, which is to be expected if a module somehow crashes.