A woodway or a peloton tread + would be ideal, but they are expensive. I have 2500 miles on my peloton tread +. Train on there all the time. Transition to outside has never been an issue. Not uncommon for me to do a long run of ~14 miles in a little over an hour and a half on there.

Life is too short for cheap treadmills truthfully.

Life Fitness commercial grade refurbished for $3200.

https://acefitnessequipment.com/products/life-fitness-integrity-series-treadmill-clst

Get the rubber pad for underneath.