Sys and system user expire date or password change date - PW related questions

1. Database = 19c - 3 nodes RAC
2. I have profile attached to sys and system user that has Password Life Time = 200 days. I am trying to figure out the password expiration date and/or what was the last time i changed the password. I checked.... a. password change date, expiry date column in DBA_USERS and b. PTIME, EXPTIME in SYS.USER$ - they are empty.
3. if I have to change these two users' password, should I just run "alter user sys identified by "n3w!!PasswordEtc". Will it break if I connect sys as sysdba from Linux db server? is there anything else will break if I change the password?