In reply to Yanis Nayu:
Thanks for this. My current orthotics both accommodate a leg length imbalance and a 'rocker' ball in the middle which my foot 'rolls' around, addressing a peculiar sort of flatfootedness that involves deformed toes rather than a low arch. Through wearing the previous orthotics over an extended period of time, my feet began to need less use of the orthotics as the muscles had strengthened, but over a prolonged period of partly not using the orthotics, and partly the orthotics being worn out, my left foot in particular is visibly back to where I started on my orthotic journey twelve or thirteen years ago, with corresponding joint issues.
Strengthening, improving flexibility, structured increases in duration and intensity are all happening - this is about mechanical intervention that has worked in the past and for which I'm looking for recommendations again