I've landed on Dokku in the end as it's the one with the least amount of "magic" involved and even if I stopped using it I could just uninstall it and have everything still running. Can highly recommend it!
The developer is also super responsive and I even managed to build a custom plugin without knowing too much about it with some assistance. Documented this on my blog too: https://blog.notmyhostna.me/posts/deploying-docker-images-wi...