The key to getting rid of rust is you need to expose all of it, so start chipping aways the paint until you find un rusted metal. If you leave any under the paint it will just keep rusting and you will have wasted your time.

I like have had good results using a stiff wire wheel on a 25krpm air grinder, it will take the rust down to good metal really fast and not harm the good metal.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200