Client certificates management

I host internet - exposed services to my family (7~ people). The services are behind nginx with mTLS. I issue a certificate per person per device (20~ certs). currently issuing, downloading and revoking is done via ssh and cli to my VPS. I'm looking for a better solution for managing this process. preferably available from my phone or something. solution must be open-source. No need to suggest writing my own code because this is exactly what I'm trying to avoid. thanks!