I did the dummy field thing for 'Ticket Details' module and this stopped the constat error e-mails. Now i can see the list of open tickets, yet I cannot open any, nor see the preview. If I click on a tickt it will not open, I tried to assign the ticket to myself but still nothing. The best result I can get is a timed out from the server, but this is probably due to cloudflare.
edit: the tickets are not opening and the apache error log is filling up real quick, i deleted a 12 GB log that rebooted my server, not sure what is causing this.
edit 2: [solved] the issue was caused by the presence of non english language as per issue here: https://github.com/osTicket/osTicket/issues/5756 seems it has not been resolved so since.