Systemd kills all background processes after ssh session ends despite all the typical solutions

I have tried almost every solution on Stack Exchange (except for nohup; it seems like that is not an ideal loophole), but Systemd still kills my background processes. I also tried starting a Tmux session as a service using [this](https://unix.stackexchange.com/a/683051/662799) question, but the processes started in Tmux still get killed after SSH is disconnected. I am using Ubuntu 22.04, the desktop version. My monitor is disconnected, but I have not set up headless mode, so I am wondering if, in the desktop version, I have to keep the monitor connected after local login. Disconnecting the monitor could cause Systemd to infer that no user is active, per [this](https://lists.freedesktop.org/archives/systemd-devel/2013-May/011006.html) email archive.