iPad mini Get the mini 6 if you have mini 4

[Kung gu]

If you have mini 5, its still a fast device. The only reason to get the mini 6 is for 2nd pencil and USB-C.

 

[dumastudetto]

Buy whatever you want if it makes you happy. If it has an Apple logo stamped on the back, it will make you happy.

 

[HarryWild]

Buy and try! If it works for you, keep; otherwise return it!

 

[Beards]

If you have mini 5, its still a fast device. The only reason to get the mini 6 is for 2nd pencil and USB-C.

Slightly smaller size: 7.69 x 5.3 x 0.25 v 8.0 x 5.3 x 0.24
Faster processor: A15 v A12
Larger screen: 8.3” v 7.9”
Higher Resolution: 2266 x 1488 v 2048 x 1536
Better Connectivity: 5G v 4G
Better Camera with Flash: 12MP Wide, f/1.8 aperture, Smart HDR, Quad-LED True Tone flash v 8MP Wide, f/2.4 aperture, Auto HDR
Centre Stage: Yes v No

And of course as you mention:-
USB C v Lightning
Pencil 2 v Pencil 1