These in-ear things never worked for me either until they started making custom hearing protection with removable filters which are compatible with most in-ear headphones. And the best thing is that you don't need active noise canceling (depending on the openness of the headphones) because the thing is made to cancel noise. Downside is that they usually amplify bass much more than regular tips so you need to use an EQ.

Btw, it's possible to get some custom in-ear headphones where everything, including the tip, is one piece of plastic, which is supposed to sound fantastic, if you're willing to spend a ridiculous amount of money.

https://dirkvanderkooij.nl/chubby

Chubby is possible but not without designing your own process/machines