If it’s really stuck I cut things like that off using a die grinder with a cutting wheel. I go very carefully to avoid scarring and leave a thin foil of material at the edge of the shaft which will break free.
Wheel bearings usually take grease. Some of the sealed type are not serviceable and are meant to be replaced. I have sprayed motorcycle chain lube on to try and get lubricant into the semi-sealed type but it’s probably more sensible to go to a bearing supplier and buy serviceable wheel bearings. They’re inexpensive and it’s simple to clean and degrease them when you do a major service.
