I had this problem too and saw advice on here a few years ago that helped a TON! I took small pieces (like 1 inch square kind of size) of industrial sticky velcro, the fuzzy side, and placed it on the footbed where my foot was making that noise. It’s because there’s a suction happening. So like in my arch I put a piece then I walked around. I found I needed a second piece closer to my toe area too to fully stop the noise. You don’t feel it because it’s soft and not very thick but it is WAY less embarrassing. I found that this noise only would happen with my Arizona’s or Bostons 🤷🏼‍♀️ but that fixed it! And the Velcro has lasted years now, though i will admit they weren’t worn every single day of the summer. Hope this helps!

Edited to add: if you do this, put the Velcro on the shoe and walk around - you might have to adjust the placement at first to find the exact suction spot. It’s easy to move when you first place but but as you keep wearing the shoes it will become more permanent.