Then you're similar to me. I setup a new truenas scale server with the intention to replace a debian server that's running dozens of docker containers via docker compose. No, it can't be done. Options are k8s and virtual machines. That's it. I can't even run borgmatic.

What I'm doing is sharing the storage via iscsi to the debian server (it's like a virtual disk image) using 10gb fiber. But now I have two servers, and the truenas one can never afford a second of downtime, if that one turns off it's like yanking drives from a running system.

Now, if I had time I could definitely learn k8s and rewrite all my docker compose yml files but I have no time, it feels like a completely different concept

The available applications out of the box on truenas scale are just 96 and only few of them are actually useful. There's a way to add a second unofficial repository (true charts) that adds another 500 apps, but the list is weird. There are like 5 Minecraft servers but not a single standalone database. No mariadb, MySQL, mongo and so on.

In addition to that, the extra 400 apps that can be installed via truecharts come with ABSOLUTELY ZERO documentation. It doesn't even explain the environmental variables. See by yourself: https://truecharts.org/charts/stable/actualserver/