When in doubt, look around. Treadmills are hopefully a long-term purchase so I’d recommend doing your homework first. Find some professional reviews from folks who know what to look for and can point out what does and doesn’t matter so you don’t get caught up in marketing jargon. I ended up picking the Nordictrack 1750 after reading up on it https://www.treadmillreviews.com/nordictrack-commercial-1750-treadmill-review/
Once you’ve read what sounds like a winner in your book, look around and see if you can test one out. This is a purchase that is all about feel. I’ve been on great TM’s and I’ve been on terrible ones. Test drive before you buy if you can!
Hope that helps!