Is Linux mint still the best for starters?
If you wanna run Mint, run Mint.
I think the perception that Linux Mint and Ubuntu are “noob-friendly” distros is overblown. There are dozens of distros that are as easy to use today as Ubuntu was when it earned it’s reputation for being friendly to new users.
Intel NUCs in specific have very good mainline kernel support, so everything will Just Work™ out of the box unless some distro has a hardline position on binary firmware.
Bluetooth, Wifi, NIC, and Intel GPU all have open source drivers.
While pretty much any distro will work, Pop OS! might have a slight advantage. System76, the company behind Pop OS!, ships a product based on the Intel NUC. This means it’ll have more testing on those devices than a generic distro.
But support is still very good for NUCs across the board, so that advantage is minor.