BrenZan the main thing about fixed location, time, and route(s) is that it lowers the required maintenance. If you’re not going to be consistently there and want something to run on its own, I think ease of administration and communication is critical…the most important thing.
With a variable route, someone will need to communicate changes; you’ll always need a ride leader. That changes the nature of the ride, requiring decisions like how to pace it, which immediately narrows appeal; some will think it’s too fast, some will think too slow, some will worry about not being able to keep up and not knowing route, etc. A whole other can of worms, which is not to say undoable, but given your level of experience and commitment, it will make it harder to achieve the desired result.
I honestly think that this is going to be hard to pull off without fanatical commitment on your part, even in the most basic format. As a beginning cyclist yourself, it’s unlikely you’re going to attract seasoned cyclists, cyclists who use navigational devices, or even those who know what RWGPS is. If they have that stuff, they don’t need your ride. If you can’t be consistent with the ride yourself, to guide it, you’ll have enough to do building your connections to a core group to do that and keep it going, so I wouldn’t advise making things any more complicated than absolutely necessary.
That said, I may be wrong, and maybe your local cycling community is ready for what you envision. I hope so.