$1200 a year is expensive but you mentioned artists. Autodesk Maya is $1600 a year, 3DSMax is $1600 a year, Houdini is $500 a year, Zbrush is $900 a year, Adobe creative suite is $630 a year.
I'm not saying you want to add another $1200 a year to that. Just putting it in perspective to "artist" expenses
The argument here is that if you want an artist to have access to your instance - even if only to occasionally use features that are available in the free tier - you have to shell out the full $1200/year.
Something like Maya or 3DSMax is something an artist can reasonably be expected to use a lot of the functionality of the product pretty often. Expecting an artist to use the majority of a gitlab license on a daily basis is a bit of a stretch.
I don't use gitlab but github has issue and project planning. I'd expect every team member to use those. Further, github issues supports easy images and videos. Great for artists, and designers to track things. Assuming gitlab does the same I'd expect the same there.
Maybe there are better solutions and so you don't want your artists do that there.
It goes the same the other way. As a programmer I've always needed a license to the same 3d software the artists are using even though I don't use it daily I might need to write or debug an exporter or script.
I'm not saying you want to add another $1200 a year to that. Just putting it in perspective to "artist" expenses