<p>Is there any DRM or license management solution for 3D printing? I'm looking for something, that would help me limit the number of prints someone can make from my projects. Basically, I would like to sell the "right to make no more than X copies" of my design. I don't expect it to be bullet-proof (like Widevine L1 for video), but it should at least help me with license management.</p>

Good luck with that.
Issues you will face:
using a G-code editor (or built-in printer software) to create multiple copies of the object in a single print session
user writing the printer file to an SD card, then block-copying the SD card
defining a "print". Specifically:
is #2 another functional copy of the object, or did #1 fail? Failed prints happen a lot.
is #3 another functional copy of the object, or was #2 damaged in post-processing? Like removing supports or left it in the acetone 5 seconds too long and it's now a blob.
is #4 another functional copy of the object, or was #3 tossed because the guy running the printer grabbed the wrong spool and made a perfectly good print in the perfectly wrong material/colour.
is #5 another functional copy of the object, or was #4 damaged in shipping?
The whole process is one-way. There just isn't a path for anything other than the end user to know what they pulled off the print bed. Unless you make the entire process from design software to printer you won't change that. And good luck selling it, 'cause the user base is rather strongly opposed to that kind of thing. For example, ANY kind of DRM in the product, from printer software to filament, is an immediate no-buy for me. I don't care if you are paying me to take it, I will find an alternative without that particular annoyance. And no, I don't use Microsoft or Adobe products either.