Repaste Sapphire 6900xt Nitro + SE Questions

Hi, I have a Sapphire 6900xt Nitro + SE and i think it needs repasting as it hits about 100c core temp and 110c hotspot and crashes in games. It was fine for the last 12 months or so, purchased 2nd hand off ebay. Just wondering if anyone has recommendations on paste / pad thickness or brands to go for. Thanks

Just replaced the thermal paste and not the pads temps went from 100c core and 110c hotspot to about 65c core and 75c hotspot