I once needed to import ics to apple calendar, but after importing, some meetings showed the wrong time. I later discovered that the ICS file was created in a different time zone.

To fix this, I enabled Time Zone Support in Apple Calendar’s advanced settings before importing again. This made Apple Calendar recognize the original event time zone properly.

Since I had multiple ICS files from different regions, I used SysInfo ICS Converter Tool to preview them first. It helped me confirm that the event time and date information were structured correctly. After that, I imported the files into Apple Calendar, and all meetings appeared at the correct scheduled times.
Read more: https://www.sysinfotools.com/blog/import-ics-to-apple-calendar/