Xpipe https://xpipe.io/ is an alternative it runs and stores your data locally on your machine and not web based. I've been playing with that a bit, it does auto discover Containerized apps and you can sort of exec into them to run commands and also browse the directories of your containerized apps with a simple click in a File type GUI. It uses your OS's default Terminal application so it won't bring any extra with you so it's more native to your OS.
I've been a Konsole user on KDE for a few years now and it's pretty much what I've been used to. Trying out Xpipe now and Termius about a year ago, I can say that Xpipe is stronger in it's ability to interface with my containerized apps (Docker), but lacks the polish that Termius has visually. They both get the job done, but at the end of the day, I still reflexively just hit my Ctrl+Alt+T key combo to log into my machines.
Then, for a whole different take, SSWifty! https://github.com/nirui/sshwifty - Instead of launching an app, deploy this on your server, and then use your browser's session to securely access your sites.