Welcome to Photrio,
@inthedark_06 !
In addition to Matt's suggestion: you could indeed 3D print a lens board. I've done this for a couple of lenses on my Durst enlarger, and the approach works. The nice thing with materials like PETg and PLA is that they're pretty soft. Hence, if you print a circular aperture of an appropriate diameter, you can simply screw/force the lens into this and it'll sort of thread itself in there without damaging the thread on the lens. Of course, you won't be able to infinitely unscrew and screw back the lens into the board, as the board will wear down. But if you just print a dedicated board for this lens and enlarger, you could just leave the board on the lens and use it that way. Printing a legitimate thread for multiple use is pretty much a non-starter given the resolution and in particular tolerances of a typical consumer-grade 3D printer.
What I did for my Durst boards was simply use an existing lens board as a template, recreate it in Fusion 360, but with a circular opening of an appropriate diameter. Works very nicely. When sizing the opening, err to the side of making it smaller so you can enlarge it a bit if the lens doesn't fit. If the hole is too small, the screw mount will get stuck halfway through and the lens won't be aligned properly. Take some sandpaper or a round file to the hole and give it another go.
It's not going to win any beauty contests, but it'll get the job done alright.