1. there is a copper plate available on online stores, it's easy to install and make sure you add thermal paste on the copper plate before fixing the cooler back, it looks like this..
2. There is also another way but a bit dangerous, you will use copper plates too but they are small in size, find the right thermal pad for your GPU, since it's 3070ti I'm guessing 2MM size will work, go on youtube and search for 3070ti copper plate install you will see few videos, see what the copper looks like below..
This second option is very effective, it can take --30°C off your mem temp if done correctly, pls watch videos before proceeding.
Watch the video
https://bitcointalksearch.org/topic/m.59773080