Finding a drive is the easy part. There is, e.g.,
Other World Computing – 16X OWC Mercury Pro USB 3.2 (5Gb/s) Super-Multi Blu-ray/DVD/CD Burner/Reader External Optical Drive with M-DISC & BDXL Support
I have the CD/DVD (only) version of this drive. Advantages include the fact that it has its own power source, and that the power supply and the cable to connect it to a computer are both detachable and replaceable. (The data cable in the box is a very short USB-A to USB 3.0 B cable, but you can find longer USB-C to USB 3.0 B ones.)
The issue is going to be on the software side.
Macs do not come with built-in software for playing Blu-Ray video discs, and third-party drives generally do not come with software for playing Blu-Ray video discs. You would need to get a drive and add a third-party Blu-Ray player application from someone else. I am not familiar with the alternatives.