This is a topic that has been tried and tested since the beginning of the Pentium era in personal computing when heatsinks and fans become the mainstay for cooling your processor and enabling the ability to overclock.
For a lot of people, this is new ground when it comes to the Raspberry Pi, as this Reddit user found out:
Source: https://www.reddit.com/r/techsupportgore/comments/f1d3mf/my_rpi_case_ripped_off_the_ram_chip/
I've personally found that a light, twisting motion helps to remove heatsinks, or ensuring it is a little warm before attempting removal.
Of course one of the more obvious is, don't accidentally use thermal adhesive
Have you had similar difficulties? Or has it been a walk in the park for you?