Double-elite night deals and status challenges are the fastest way to do it but in my experience, it’s hard to count on doing either (and the challenge can typically only be done once every X years, not sure on the particulars). The good news is that most of the time those types of things stack. Meaning that if you are on a 16 night in 90 days challenge, that can stack with a double elite nights promo, meaning you’d really only have to do 8.

You may want to check with your employer to see if they have any deals/promos with Marriott. This usually requires a larger employer, but it’s worth checking out because it can loosen the elite requirements.

That said, if you’re not going to spend 30+ nights in hotels a year, I’m not sure the benefits are worth the time/money. That’s subjective, I realize — but something to keep in mind.