HAProxy is this a Good Use Case/Is this possible/practical

[guardian]

I would like to have an easy way to access self hosted cloud services (Nextcloud and possibly others) from behind pfSense on my home internet connection using Android, and Linux clients.

I like that OpenVPN can use TLS certificates to essentially ignore unauthorized clients, and being able to do this with other web apps would drastically reduce my footprint for attack.

Can HAProxy demand and check client certificate?
(From what I have read it looking at the UI in pfSense, it looks like it is possible.)

If so, is it practical to have multiple certificates (No more than 4-6)?

I know this is more of an Android/Linux question.

Is implementing a client certificate on Android just a matter of importing the certificate to a system trust store, or does each application have to support client certificates?

I did some googling around Android TLS client certificates, and everything I found was java client programming related. Can anyone suggest a targeted search term that will get me relevant answers.

Any input/suggestions would be very much appreciated.