So much depends on your workflow, hardware, and work requirements.
I personally think you should figure out those things first and then see if you can achieve that with OSS.
If the workflow of Ableton is what you need or prefer then I would say just switch now and use that. Some style of music appears easier to produce with Ableton. Clip launching, loops, that kind of live DJ type stuff.
If you're looking to stick with the Pro Tools style workflow then I think you should stick with Ardour. Their documentation used to say that if you didn't know how to do something and it wasn't in the manual then just look at the Pro Tools docs.
My background....
Back in 2008 I started off fresh. Only knowing how to use Audacity and switched to Ardour because it was too hard to get a decent mix when all you can do is destructive editing. I switched to Reaper for MIDI work two years ago but I still export from that and finish tracks off in Ardour because I prefer the mixing and mastering process in Ardour. It's just more familiar and I can get what I want faster.
Sorry if I assume you're less experienced than you are. It seems like you've got an insane amount of musical skill but you're new to the recording aspect.
If you're just getting started in audio production then I think the most important thing you can do is learn the general concepts. How you do implement these in various DAWs might be a little different but most likely you're going to be using the same concepts (compression, sends to reverbs, bussing, etc), plugins, the same hardware, and all in the same room. Basically, I don't think the software you use is the largest factor in the potential for your music. Composition > performance > sound treatment > recording quality > the other stuff.
One thing I can say for sure is that if you're going to be recording MIDI data in Ardour you'll probably not have a great time. I used to think it was fine until I tried Reaper. There probably have been some improvements to it since I've used it last and I know they added a clip launch feature to be more similar to Ableton but I just don't think that's where Ardour shines (which is tracking, mixing, and mastering).
Also, if you ever need help with Ardour you should stop by !ardour@lemmy.studio.