What should I use my RPi4 for?

I have a unused RPi4 (the 8Gig one) running DietPi. I did use it as a playground but ever since I am renting a Hetzner machine for (playground) stuff that I want web accessible, I don't have particular use for the Pi.

I am currently running (outdated) Home Assistant on it but there isn't much I can connect it with (yet, getting the flashable/compatible ikea smart lightning zigbee? bridge thingy is on my bucket list). Obviously I do have a pihole there.

Shoot me any other ideas I could run there. Some kind of monitoring of my rented infra would be cool (I already have uptime kuma on the dedi hetzner box). One idea I had was if there are some OSS security scanning "daemons" I could use on to monitor my other infra.

Thanks a lot!