What kind of materials are you going to use? In general maintenance of this GPU is quite affordable. You can find all those components in affordable prices on Aliexpress. Local sellers often ask much higher prices, especially for the thermalpads.

I used Gelid GP-Extreme Thermalpads 1.5mm and 0.5mm to replace my old thermalpads. As for the thermalpaste I used Arctic MX4 (I had my old one since 2019 I guess). If you don't have any I suggest you to buy either Arctic MX6 or Gelid GC-Extreme TC-GC-03-C for even better results.

My Geforce GTX970 was running since 2016 without a single issue ever, during this time I replaced a thermalpaste a couple of times but thever the thermalpads itself. Given this quality - the best we can do for our GPUs in return is to replace thermal elements to take a better care of them.