I did this on my fiancés DS a couple of weeks back. It was an easy job in all respects. Didn’t need to undo the engine mount. All work done from below aside from refilling the coolant.

I followed this YouTube vid for guidance.

https://youtu.be/ohl7qaa0VEg?si=q0pUWQWaAw5-mh-H

The kit I used was a Gates from

https://ebay.us/m/WI01ib