If you want to refine your technique, pick a very neutral monometal (gauntlet, dang 2, etc) and play and don’t stop playing. Find what you’re bad at and find a way to do it properly.
From experience, changing any other variable besides how much you play is not significant. Fixie is good but you don’t learn how to get smoother because you’re simply not practicing the same things, it’s an entirely different style. Same with responsive, kinda, but it’s not quite the same.
You know when you start to refine technique? When the length of your combos rises. Combo stamina is the characteristic seasoned players have that beginners and intermediate players lack.
And you know when does the lenght of your combos rises? when you learn to perform every element and transition cleanly and efficiently, so it takes as less spintime from the yoyo as possible.