I work on the exercise equipment field. Sure enough, right now everything is sold out and demand is jacking prices up.
My recommendation, if I was to buy a treadmill for me, I would go with a used commercial grade. You have residential and commercial. Residential have light weak parts, made to be used sporadically but break easy, they even fail just by not using it for a while. Repairs are still expensive.
Commercial treadmills are made to be work horses. They are for gyms, intended to be used by multiple users, 7 days a week, 365 days a year. They are bulkier, but way more solid, heavier with hardcore components that last longer and fail less.
If I decided to buy a new residential one, I would go with a Sole. (Sole belong to Spirit) The reason, they have EXCELLENT customer service and warranty. They cover any failure, I believe for 5 years, you call them, describe the problem, they ship you the parts and they arrange with a local service provider to go and repair it. No cost for you.