I just bought a Mavic. I was curious which frame rates pilots are using to get the most cinematic footage while editing in Premiere Pro. Is it best to just shoot 24fps 4k or
shoot 30fps and down convert in post for smoother footage? Tks!

I always shoot in the higher fps setting possible no matter what resolution....

2.7k @ 24/25/30 fps is the sweetspot with bitrate vs compression.
4K @ 30fps is 60mb/s and is no where near 'true' 4K. On the P4Pro, 4K is 100mbs with the H.265 container and that to me is 'usable' 4K (usable is subjective).
If you have processing power, film 4K@24fps and downscale to 2.7K or 1080p for quality.

You will probably find that 30fps will give you a smoother pan than 24fps. Just try a video using each frame rate and pick the one that is the best for you. If you are able to pan smoothly then either will be ok.