OK. First, i never sailed a SUP so I can't give you self experienced advice on that. But here goes some thinking around the subject...
As I see it you have two options. A Kombat 105 is not one of them. If you go the windsurfing route, I think an EVO (90 or 100 depending on weight) will be a much better choice if wave riding is your priority. Particularly since you state you want to improve frontside wave riding. An EVO simply make the hardest parts of wave riding easier. So in short, an EVO is pretty much guaranteed fun in the conditions you describe.
But a SUP could still be a smart choice. Even though I'm a pretty OK wave sailor myself, I've learned stuff that was good for my sailing by stand up paddling. With the shorter more "modern" boards you can turn rather radical also in smaller slower waves. I'm pretty sure that if you liked longboarding bar the "swimming", a SUP is exactly what you look for.
And judging from what I've seen, the short SUPs can double really well as windsurfers without being at all as bulky as a longboard (through a dedicated longboard surfing SUP will surely be a much nicer experience than an old windsurfing longboard). If this sounds intriguing, have a look at the Starboard Extremist 9.0 or 9.8. I don't think they will be as radical as a big EVO, but they will take wave sailing even further into light wind territory for sure. I'm very keen on trying one with a sail myself (the SUP I currently have does not have a mast cassette).
I'll see if I can get some of the guys who has sailed the SUPs in here. Hold on.