

Presumably given they’ve all been released in the past few years and are still getting updates the manufacturers would release an update disabling the functionality to comply with law. Same with end user devices removing the functionality via software update.
You’d have a small percentage of holdouts who have auto updates off and also refuse to apply it manually and who also have non-updated computers or smartphone. They’d leave it up to whoever buys the spectrum to locate illegal use like this based on detected interference in their usage, report it to the FCC and they send you a nasty letter followed by debilitating fines and a legal order to seize your equipment if that fails.
In practice people who go out of their way to avoid the updates that disable it will probably see no consequences but decreasing benefits as well and will eventually update or replace devices.
There is no special burner that turns regular DVDs and CDs into M-discs. M-discs were a special product that were special because of the disc itself. This doesn’t answer OP.
Lessons from this were applied when designing BluRay discs which are much more resilient than DVDs.
M-discs are just premium BluRays now. Probably not worth the difference in cost given you can buy two BDs from two different batches for the same price as one M-disc. Just avoid LTH BDs which use quicker degrading components.
M-discs are a meme that were made for and only had relevance in the DVD era.