Swapping out a groupset on a rim brake road bike is pretty straightforward as most components can simple be replaced.
In your case there are a few special considerations.
You correctly identified that you may need to replace the rear wheel. This is because you either have a 7 speed freewheel type hub or a freehub tyoe with a narrower 7 speed freehub body. However, you possibly have a 8/9/10 speed freehub, and a spacer behind the 7 speed cassette. if this is the case you will not need a new wheel. The 2020 RC100 page does not specify what hub is used.
Thee RC100 does not have a front derailleur, so the frame may lack mounting points for front derailleur cables and routing through the bottom bracket area. A clamp-on style derailleur mount will be necessary of course.
You'll need to replace the bottom bracket along wth the crank. It's very likely the crank is a three-piece with square table axle. You could find a double or triple crank that (probably Claris or Sora) that is square taper, but the axle length would probably be incorrect for the different cranks.
Rim brake groupsets are relatively cheap these days, but bear in mind that it will still be a significant cost compared to the original proce of the bike, especially of you have to replace the rear wheel. Also. you'll still have the heavier lower-level frame and other components. Another option to consider is a new Claris or Sora equipped bike, so you get an upgrade of all the components.