Don’t try removing the heatsink. Just remove the fans from above it and put them so that they blow ACROSS THE BOARD rather than just down onto the top of it.
I know. I had a vertical fan before. And I agree, with great success. Now, this setup is mechanically sound and nothing is lingering around with about equivalent heat characteristics.
Another reminder:
DON’T TRY TO REMOVE THE HEATSINK!!!
I was stupid enough to try, the EMMC chip broke and my board is a dud now.
hope to have warned you all properly.
I decided to take the risk, as my device does not boot anyway. I decided to use the fact that the CPU chip is a bit taller than the UFS chip, as already noted by someone. Thus, there is more thermal paste above the UFS chip, and it is easier to reach. But first I put a lot of BGA Ic Adhesive removing liquid under the heatsink. It’s chemically very aggressive, maybe it relaxed the thermal paste a bit. Then I started to cut the paste above the UFS with a snap-off blade very carefully, and the heatsink disconnected without almost any force. The condition of my device has not worsened, but as I mentioned, it won’t boot further after trusted firmware - perhaps the UFS chip is dead anyway 
