My two cents:
I have been running Shimano Dura Ace 9000 drivetrains on my V20 and S30 for years now with no shifting issues ever, front or rear. I like close gear jumps and run 36/50 oval chainrings and 11x28 11-speed cogsets on both. Again, shifting has given me no issues after many thousands of miles. The equivalent Shimano Ultegra group has the 6800 designation. These are both previous generation groups, once removed, but the current 9100/8000 series might be just as good, if not better. And the 9000/6800 groups are still available if you look around (I bought most of my Dura Ace parts as "lightly used" on eBay and they have been great).
I have built my own wheels for years now, and I love doing it because I can build the exact wheels that I need for a given bike. For example, I weigh 130 pounds and climbing is my strength, so I know that I can get away with building lightweight, lower spoke count wheels, even on my two mountain bikes. My Clydesdale buddy, on the other hand, beat the crap out of his aluminum OEM wheels, so I build him a set that came in lighter (thanks to carbon rims), and has held up for two years now without a complaint. I don't want to make it sound overly simple. It isn't. But neither is it the impossible voodoo that some people make it out to be. I started by reading the immortal Sheldon Brown's advice on wheelbuilding--may his saintly soul reside amongst the cycling gods.
https://www.sheldonbrown.com/wheelbuild.html
Speaking of carbon rims...I pummeled a few aluminum rims on my first Cruzbike, my V20. Unlike an upright bike, you can't pull up or hop over road debris or potholes. I try to ride around it all, but I still hit things on occasion. And on a V, I might hit something--a small rock, or the edge of pothole--at 25 mph or more. Nothing that would cause a crash, but enough to make front wheel say "ouch!" After denting three aluminum front rims, I switched over to carbon, and it was an excellent move. Stronger and lighter. I have four seasons now with the carbon wheels on the V20, and three seasons on the s30, and both sets are as round and straight as new, even with lower spoke counts--24 front, 20 rear. The issue with carbon rims has traditionally been cost, but there are a few Chinese carbon manufacturers that have good reputations while offering affordable carbon rims. I have used both Nextie
https://www.nextie.com/ and Light Bicycle rims
https://www.lightbicycle.com/ with excellent, long lasting results. Light Bicycle even has an American distributor now. In my opinion, the old nightmare stories about "cheap Chinese" carbon rims that you read about online don't really apply these days. There is still junk carbon out there, but there is really good stuff out there now too.
Finally, my V20 has fancy, expensive DT Swiss 240 hubs, which have been great. My S30 has Bitex hubs--slightly lighter, and less than half the cost--which have been just as solid, fast, and smooth as the 240s. My s40 and one of my mountain bikes also use Bitex hubs, and they have been bombproof. I buy them from BikeHubStore (they have decent prices on spokes and nipples as well).
https://www.bikehubstore.com/
However you go about it, enjoy building your bike. Very exciting.
