Run firefox as a different user in Kubuntu

I want to run Firefox as different users (Kubuntu 24.04). I've created extra users, then I do $ xhost +SI:localuser:NEW_USER $ sudo -u NEW_USER firefox I get this error message: /user.slice/user-1000.slice/user@1000.service/app.slice/app-org.kde.konsole-32c90ac053c74c8b88698b978c0ba6b5.scope is not a snap cgroup Digging, I've come across these: how to make it possible using SSH and using systemd-run The SSH method works, but I don't want to go that route. Now, I run this command: systemd-run --uid=1001 --slice=user-1001.slice /bin/sh /path/test.sh test.sh writes into a file that only user uid 1001 has access to, and then starts firefox. Checking, content gets written, but Firefox doesn't run. Checking with ps, there's no firefox process. How can I get Firefox (installed as a snap) to run as a different user?