GPU Fan Sticking

Hey so I have a Acer Nitro 5 from 2019 (I9300H + GTX 1650) and recently I’ve noticed my GPU fan struggling to get up to speed. I haven’t spilt anything on it for about two-three years and just maybe 4 months ago I noticed this. I don’t want to take off the heatsink as I don’t have thermal paste just yet but if yall have any tips or reasons for why this is happening that would be great! For info the fan used to spin at 6112 RPM at max and now it has a max of 4000 with the average being 3700.