selfhosted webapp for employee availability within company?

in my company there are a lot of people doing part-time work, and with the advance of remote work it's getting difficult to know who is in, who is wfh or who is available at all. there exists a page on the wiki for holidays and days off and a seperate calendar for pto, but checking it is bothersome.

i've searched around but didn't find anything fitting, do you know of anything?

requirements: permanent days/hours off (during work hours), permanent wfh days, one-time holiday/pto, easily searchable; optional: integration with chat, e.g. matrix

cheers!