redmine - install a second instance with different ruby version

i tried to create a second redmine instance on one server, but also with a different ruby version. I firstly switched to 2.6 ruby version with rvm, created a second DB, a second user and of cause a second redmine folder in my opt directory.

Then i proceeded with the same steps of the installation as in the first one.

When i finished the installation, the information page of the second redmine instance told me that neither data or pluginassets were writable, also the ruby version was the same as with the first installation (2.7).

Is there any part of the docs i dont know which tells you on how to correctly install a second redmine instance? I think in this one i messed up Thank you so much for any reply