dlb I looked about a little bit and found nothing. I'll look again in a few days. There used to be sites that'd run an NMAP scan; some tailored with malformed packets, etc.
It'd be very nice to find a site that'd send SMS tests; including zero-clicks.
There are likely chat rooms that specialize in Android security testing - e.g. here's one for Windows and a little bit of Linux: https://www.grc.com/discussions.htm.
Maybe you can get something interesting going at https://app.element.io/#/room/#grapheneos:grapheneos.org
Please post here if you find anything!