My big question would be why are you starting with a dual boot? I would recommend trying each one with a liveUSB or in a virtual machine and simply do a single boot with the one you like better. There’s likely little need for you to actually maintain two distros unless you have a very niche use case that one distro can’t solve.
My advice would be to just relax and realize that the underlying OS is 90% the same regardless of what distro you choose. All the discussion you see on different distros, package managers, snaps, wayland, etc. are all the other 10%. It really doesn’t matter what distro you start on as long as it’s a general purpose distro (both of the ones in your OP are): once you learn the first 90% of linux, you’ll develop your own tastes, and then you’ll be able to decide on the remaining 10%.