Rootless container in linux multiseat environment for desktop application deployment?

i found docker convenient to deploy desktop applications which are difficult to configure, i published a geogebra development environment in docker hub.

i tried rootless container on desktop:
userns-remap:testUser

the uid for testUser is 1000

and in /etc/subuid, i have
testUser:1000:65536

when testUser create a container with docker run, i can see that bash in container prompt root, while the process account shown as testUser on host. That is what i want.

but suppose we have another user in host named testUser2, and testUser2 create a container with the same image, and we need bash in his container prompt root too, while the process account shown as testUser2 on host. Can we achieve this?

Usually, we use only one account in PC desktop, but what if serveral people share a PC, such as in a linux multiseat environment?

i just know that i don’t have to use rootless container configuration for this, i can use docker composer instead, and specify different user in different yaml files