docker-swag VS vouch-proxy

I have a NAS on .0.181 and a swag container (on a different port than nginx) on .0.180 that points to my public facing services. For obvious reasons, I don't want my public domain to point to any other ports/addresses on my home network. Additionally, as elegant as swag is, it requires authentication and so won't work for simple local DNS. I now have one local domain for each server and an nginx instance on each that resolves to my different services on each.

OP is even linking the Github... https://github.com/linuxserver/docker-swag

I have an UnRAID server with a few services (Jellyfin, Nextcloud, etc.) running on it behind Linux Servers' SWAG reverse proxy container, which is built on Nginx and Let's Encrypt. This is pointed to a DuckDNS link, which is then pointed at my domain with a CNAME. So I can access Jellyfin, for example, at jellyfin.mydomain.com. A few weeks ago, due to seemingly unrelated issues, I got a new modem/router, an Arris SURFboard G34. For the first few weeks, everything was working as before. But now, when on my LAN, I can't get to my services at the proxied domain. It times out every time. There are no errors in SWAG's logs, nothing seems amiss in the router's web interface, and the services are available both at their IP:port address and, when not on my LAN, I can access them at the domain no problem.

Reverse proxy, probably? I use Docker SWAG, setup here, with DuckDNS and it works really well for me. There are of course many ways to reverse proxy, as I linked to earlier.

Look into vouch proxy

Vouch proxy is designed for this usage: https://github.com/vouch/vouch-proxy I don't think there are any nice UIs to configure it though so you'll need to be familiar with running it yourself.

Not sure this is a "best practice", but it lets me keep control of the Ingress resources inside their YAML configs. I've also layered Vouch Proxy into the ingress configurations to require SSO/MFA auth to access the resources behind the Ingress. Cloudflare has the ability to do this, but I found it cumbersome to keep track of the configs outside the K8s cluster.

I've used vouch proxy for my own stuff previously, before more recently moving to Cloudflare Access. vouch can be slightly janky at times to get working right, but once set up, it's been solid.

For example: nginx -> Vouch proxy -> KeyCloak -> Jellyfin

While this works, we were hoping to make access a bit easier with say an OpenID Connect SSO and reverse-proxy solution. I've seen Vouch Proxy, https://github.com/vouch/vouch-proxy which is really just SSO on top of nginx, but I'm wondering if there's a simpler way to do this.

You seem to be quite knowledgeable and a minimal provider with just the bare minimum would suffice for you. Have a look at Vouch Proxy, it does one thing and it does it well.