First question, why not remove them? If you must cut them then the best option may be a jamb saw. They use it to cut the door jambs when you install thicker floor covering like a laminate over a floor that had just vinyl or you install ceramic tile on a floor that had some other floor covering. You can rent one at HD tool rental.

https://www.homedepot.com/tool-truck...amb-Saw/10-55/