@Rob4
The Blu-rays of the 2021 restorations are currently at $5.99 (four of them) and $6.79 (two of them) on Amazon for the Kirk films.
That's $37.54 for the six whereas two 4K's would set you back practically as much at $36.
If you really wanted them on 4K and were a real fan you'd already have them. Meanwhile the blu-ray's look and sound fantastic. They also look good on the shelf together with the Picard set i posted above