Unfortunately I can’t assist with your other question about a proper cable as I still suck at picking them myself, but I can with this.
Some IEMs have a recessed 2pin port, which allows that little plastic extension to slot in and give it some extra protection. My Szalayi is like this, I cannot use cables that don’t have it with that IEM. If the option is there, it will be labeled as “recessed 2pin”.
Also, the recessed 2pin helps add a little length to the post for people with larger ears. I pretty much can’t use a cable that doesn’t have it, as it pulls down too much causing the same exact unsealing issue you mentioned.
Hope this helps, xinhs/ivipq cables typically have an option to select one or the other.
Edit - also if you like a cable on AE but it doesn’t have the option, always worth it to try to message the seller to see if they can accommodate. I had my next round of cables made modular and with different chin sliders by messaging ivipq.