Axum

The closest project to this that I can think of would be Netbox

The bitwarden vaults themselves are encrypted with your password. So I’m not sure what there is to not trust with bitwarden, as even if files were stolen, they are encrypted so they’re largely useless.

I pay for bitwarden premium because it supports the development of a good open source project.

Edit: fixed phrasing given suggestion below

If it’s just android, you may look at Headwind mdm

https://h-mdm.com/

You can get a quad core ARM 24 gb ram vpn for free on oracle cloud on their free tier.