This procedure is usually done on cards that are past their warranty period, or were used for a few years. You didn't find a lot of info about it because 5700XT is a relatively new card, so there's no point in doing it yet.
The idea behind GPU repasting is that after a few years of use, the thermal paste can dry out, maybe oxidize a bit, maybe slowly slip out. In that case you can maybe gain the 10c you talk about. Between "fresh" pastes, the difference is going to be 5c MAX from the worst paste to best.
Delidding is not exactly the right comparison here. The process is maybe a bit similar, but the temp difference won't be as significant. With Intel, you don't get variations of the same model. There's no "EVGA 8700k" or "Aorus 8700k". People are going to buy the model they want because they have no alternative. With GPUs that's a different story, and reviewers always compare things like thermals and noise between different brands. So on GPUs they won't use the most expensive thermal paste around, but they use something that's good enough.
If your card is still under warranty, and it runs cool without issues, then don't bother changing thermal paste. Whenever I see a used GPU with the line "Thermal paste was changed recently" then I know that most likely the seller has an overheating GPU, and he tried different methods that didn't resolve the issue and he can't use the warranty. The procedure itself is safe, but it's still a procedure. You never know what can potentially happen when you unplug your PC, remove card from PCI-E socket, take apart some fan or LED connectors inside the GPU, loosen the thermal pads, etc.