Mark it as busy in the calendar, that might keep them away. If marking the whole day is suspicious, make 1-2 hour marks with 10-20 minute gaps (or longer as long as it doesn’t allow sticking a meeting in). Then make these “appointments” weekly and set the subjects(focus time) to private.
Looks like 2023 will be remembered as the year of big size enshittification. So many companies going to shit. Reddit with restricting API access, Twitter with…everything really, Google with its DRM and now Unity…great year so far, right?