It depends on how worn they are. You could probably reused the gliders if you are careful when removing them. I did end up replacing mine though. Here’s some replacements: www.aliexpress.us/item/3256805149791432.html
I can highly recommend this! The switches are very cheap and I love my silent G305. The hardest part was probably the middle click button but you can skip that one if you don’t care about it as much. While you’re inside, you could clean the scroll wheel which might fix your swelling problem.
I am not very skilled with solder and found it very easy. You don’t need anything fancy like a desoldering gun. Just a regular soldering iron with some solder and flux worked for me.