Mixing different frame rate in a Timeline issue

Some of my clips are shot at 30fps and some are 60fps, I prefer exporting the project to 30fps. Will it be a problem if I add 30 and 60 fps clips in the 30fps timeline? Do I need any frame blending in davinsi or any extra work?
My footage is shot at GoPro 8 at 30fps, but I dont know why it shows 29.97 fps when I import them into media pool. Any idea why?
My footage is shot at GoPro 8 at 30fps, but I dont know why it shows 29.97 fps when I import them into media pool. Any idea why?