What to do with a Raspberry Pi 4?

When Raspberry Pi 5 pre-order was announced, I considered getting one to replace the Raspberry Pi 4 (RPi4), one of the servers in my home network. At that time, I also discovered a couple of Intel-based Mac Minis up for sale, and I couldn't resist, even justifying that it blows the new Raspberry Pi 5 (RPi5) out of the water in all aspects, except perhaps power consumption. The RPi4 lived another day or months, for that matter (I have yet to reboot it with an uptime of 84 days as of this writing). And the Intel Mac Mini? I upgraded it to 16GB and instead of being the home server, it is now one of the desktop computers used by the kids. Talk about botched plans. 

Now as I wait for the delivery of the Raspberry Pi 5 kit (8GB RAM and 1TB SSD), I need to plan its purpose. The RPi 4 used to be the Pi-Hole + Unbound + Wireguard VPN, PlexMedia and Samba server. Today, its main purpose is a media server running Plexmedia. The external storage  shared on the network was transferred to the Asus wireless access point (it is a router actually, but configured only as an access point). The Pi-Hole, Unbound and VPN were concentrated on a Firewalla that acts as the router, IPS/IDS, DNS, DHCP and VPN server. However, even with reduced load, the RPi 4 with 4GB of RAM and running off of an SSD chokes when serving high resolution videos to the Apple TV. THIS will be the primary function of the new RPi 5 - hoping that I won't see those stuttering and lag anymore.

I know that the configuration of the Raspberry Pi 5 is a bit overkill for running just Plexmedia, so I am exploring what other services I should run off of it. I already have some self-hosted software, e.g. NextCloud and an RSS Feed Aggregator,  up and running elsewhere. I use Signal, iMessage and FaceTime, instead of running my own Jitsi, Matrix and XMPP servers. I could host my own Mastodon server, but I decided not to, instead I subscribe to omg.lol. I already have a multi-user Wordpress instance that serves the kids' blogs and my blog archive from Micro.blog, another service that I subscribe to. So what else is there to self-host? 

Homebridge. I have a few I(di)oT devices, but these are all on HomeKit. I do not trust other platforms. It is HomeKit or bust. This restriction means having very limited choices. Should I run Homebridge so I can widen my choices with devices supported by Homebridge? Or should I just wait for Matter to be widely supported. 

BaseRow. I use Baserow.io, a hosted no-code database service, to monitor which articles I have submitted are published and went. Baserow is open source as well - so this is a candidate for self-hosting on the RPi 5. 

PhotoPrism. I have Flickr Pro and iCloud that host my photos and videos. I back-up using PhotoSync to a local networked drive. Having a local Flickr/iCloud Photos like application with de-duplication might be a good idea. However, the 1TB storage won't be enough and without multi-user support, it might not be an ideal setup.

n8n. I used to have a lot of workflows hosted by IFTTT. Since they decided to reduce the number of free workflows, having n8n instance might just be an attractive option. Will play with the free n8n account and see how easy it is to use first.

What else should I consider to self-host, any suggestions? And whilst you are at it, what should I do with the Raspberry Pi 4?