How often do you replace brake cables?

Clean it properly first, half of these problems are just dirt.

There is a good guide on this in the Articles section.

Sounds like the bearings. They are cheap and easy to swap.

Solved it last month with a new cable. Night and day.

Make sure the wheel is seated fully in the dropouts.

Marking this one to follow, same issue here.

Check the simple things first: tension, limit screws, and that everything is tight.