Yes a bike computer (I use Wahoo Bolt & Roam) will display power figures.
You can display instantaneous power, but I find displaying a rolling 3 second average is of more use.

For wheels I purchased Mavic Ksyrium Elite UST (rim) and have 3,000 miles on them. I think they are great and very light weight even compared to a pair of SuperTeam or equivalent..
I'm moving to a disc bike and have ordered the same wheels in the disc version.
The disc bike came with Ksyrium on it but not the UST version, hence the replacement. Tubeless has proven to be great.
I also chose to stick with the lighter alloy wheels because I don't travel fast enough to need the deeper rim that Carbon provides and I'm 200 pounds.

If I was riding alone, I buy the PM first. After all, you want to judge your performance and not how fast the bike travels.
If I spent most of my time in a group, I might be more interested in a wheel replacement.

I recently got a cycling coach. Turns out I was self training all wrong. All of my training is now performed using heart rate (HR) zones.
Power Meter (or indoor smart trainer) helps set those HR zones.

All the best

Barry