All of this is subjective, and your mileage may vary.

• There is a lot you can get out of seemingly over- or under-exposed images.
• Do not use it on a per-file level. Just open the entire directory and edit what you like.
• At least for an EOS M50, the camera's auto white-balance is probably better than trying to get it right manually. Unless you have a white card or wanna go for a special style, of course.
• Copy-pasting (parts of) post-processing configurations can be super helpful, but do be careful.
• Just play around with sliders until you like the result. It's art; there is no right or wrong.
• Some features (like Dynamic Range Compression) will look great on some and horrible on other photos.
• If highlight compression gives you pink image areas, try a different highlight reconstruction method.
• RawTherapee is very conservative about the EXIF tags it exports by defualt.
• .pp3 files are just ini files, and you can easily adjust them to, e.g., include more EXIF tags in the exported JPEG files.