There’s really no need to reverse proxy ssh. What are you attempting to accomplish with the reverse proxy exactly? Http proxying allows you to add things like TLS encryption and modify headers. But ssh is a secure protocol already and you can’t really modify much in transit.

Would only be worth it if you created a system for easily deploying applications on an already set up subnet with routing preconfigured.

Like set up a single server kubernetes distribution like microk8s or minikube on the server with metalLB and ingress already preconfigured on the server and router. You could also give instructions on how to install a GUI like Lens and how to use it to deploy a few things. Probably using workstation applications would be better than a web UI like Portainer to keep the server lighter, but either might work.

Yeah, you definitely should run it on a separate machine. A home NAS itself probably shouldn’t be doing anything beyond serving files and basic maintenance. Using them for too much will reduce their ability to serve data fast enough. Just be sure the media server and NAS have appropriate network cards, preferably gigabit, though even 100Mbit probably is enough for most of your network isn’t already too busy, and ideally are connected to the same switch (again preferably gigabit) with good quality network cables.

Use Drive or if it’s more than 15GB or whatever the max is these days. Pay for storage for one month for a couple of dollars on one of the supported platforms and download from there.