Changing the calendar names

Yes, you can. ??

You need to use the customLabels option like:

customLabels='{"google":"guuugl"}'

Keys would be google, apple, ms365, msteams, outlookcom, yahoo, ical.

You can find more details at: https://add-to-calendar-button.com/advanced-use#case-4

The PRO version offers an even easier way of customizing those things, if you want to check this out as well.

All the best!