I had the same problem with blisters under my big toe and tried various all possbile solutions—different shoes, powders, creams like Compeed, and expensive socks. Eventually, what worked for me was a combination of well-fitting shoes, quality socks (I use Falke TE2), and small, smooth patches placed on the insole where my big toe rubs (not on the side but at the bottom). The patches aren’t as large as the one shown in the picture—just enough to cover the area of friction. At first I was really skeptical, but playing with it the first time I was so happy that I didn’t have blisters or any toe pain. A bit surprisingly you actually don't really notice the patch and it doesnt hinder in any way.
Here is an example picture, tough my patch is much smaller and only under my big toe:
https://preview.redd.it/gc5o9nnl3krg1.png?width=589&format=png&auto=webp&s=dfdb204968d93b09ef7baafd59b3f2d8d1be0834
Which patches do you use? Do they stay in place after hours of playing?
https://preview.redd.it/03ne6elu3lrg1.jpeg?width=1280&format=pjpg&auto=webp&s=26f4396f7615ce7e6914e52c7c0d7ba714a0959b
They look like this on the insole. I bought them in a local drug store in Austria, but at least in Germany/Austria there are some available on Amazon.
I have around 20-30 hours with this patch and it is still glued firmly in place and smooth, so quite happy with it. Even tough, they were relativly expensive (around 12-15€ for 6 pieces).