Search in Calender doesn’t show

After I switched from iPhone XS to 13 and synchronised from iCloud it doesn’t work to use search, I type f.ex. „Sara” with no result, while I look manually at particular day and there is „Sara”. It works to

find events that I added after mobile change but now for ones added before, though they are visible in calendar. Very irritating cause I have all of my work scheduled there with customers 😭 Help 😵‍💫