Sadly I only took afterschool tai kwon do and so my knowledge of this is limited. But I do have an appreciation for different styles. Yeah I agree the thing I noticed is that with lightsaber dueling, they don't seem to care much if you experiment with your lightsaber skills. Once you learn the Forms you are free to experiment and invent. I rather like that. And we see that in Darth Vader, he modified his fighting style to match being heavier and less agile due to his suit. And he became an absolutely lethal fighter. Bariss Offee pointed out to Ahsoka that she favored a form of Djem So, but suggested Form VI as being more effective in combat against her.
In my experience (Taekwondo) a form is not a style of combat like it is with lightsabers in Star Wars, but more of a sequence of moves that serves as practice. A choreographed sequence of moves.
In this clip from Rebels, you can see Anakin performing a sequence of moves to a count (you hear him counting one, two, etc.). This could just be a drill with a series of moves, but that's still fairly similar to a form, or kata, where you perform a sequence or series of moves, often with a common theme throughout, to help teach and practice a given skill, movement, or idea.
Certain forms/katas can of course be more or less useful for a given from/style of lightsaber combat, with different moves, pacing, speed, etc. but you can practice many different forms/katas all with the same form/style of combat, if that makes any sense.
As for the various lightsaber forms, it does make sense that one would adopt a style suited to their skills, or even adapt a style further to play to their strengths and minimize their weaknesses. We see Vader and Savage use their strength for example, while Maul and Ahsoka use their athleticism in combat.
I entered into Taekwondo quite some time after beginning and becoming very familiarized/regimented in kendo, and I at first gravitated more towards Kumdo. I enjoyed using the same gear in that respect. Although the two are (at least in my experience) rather different in ways, reflecting the origins in different cultures but also the differences in style. I thoroughly enjoyed taekwondo for many reasons, but (and possibly just due to the fact it was a different instructor and/or "school") it always struck me as markedly more aggressive. The two also of course had completely different names/terms since they were grounded in very different languages. It was a wonderous growth experience, but at first rather disorienting to relearn new titles for everything. Though yes, I did love almost all of the forms (the drills of movements) in it! They made me think heavily of kenjutsu when using a sword, because everything was so geared toward interesting movements and attack patterns from the get go especially in multiple directions and vs multiple envisioned opponents. Kumdo seemed in many respects a far cry from Kendo, but previous training prepared me to pick it up faster and made it very rewarding. I'd also call it a good basis for lightsaber training, just like the Bo staff was great fundamentally towards the saberstaff. Not to mention all the taekwondo kicks that (as SirLift would surely say) could theoretically be useful in true lightsaber combat. Martial Arts are truly fantastic, and those times will always have such meaning for me. But Kendo will always hold a special place in my heart.
Even though I've learned so many things since the first bits, it's like JoleeBindo referenced "the skills are perishable, and rust accumulates" but I've found the mechanics tend to stay the same under it all. Finite motor control may not guide the blade right back at first with pinpoint precision, but the pieces remain just waiting to be put back together. A body never fully forgets those things etched into it, when carved deep enough through endless repetitions. I always find myself snapping back into it remarkably fast, but I suppose I've rarely allowed myself to be "fully out of practice" or abandon the mindset entirely. It just runs too deeply, and a sword of some sort is rarely far away. We all have our passions... and through passion I gain strength.
I must agree with the ideology of adaptability. I've tried to mirror Bruce Lee in adapting my personal fighting style or variations as need arises. I like both of your mindsets there. I've learned much all to find what works best for my body type, the variety of situations our world generates, and my own preferences. Such a thing is by no means easy, but is a worthy effort of a lifetime in my way of thinking. Never regretted the effort even once. MA are truly meaningful.