Is this a flaw with the hookless rims beloved of the wheel manufacturers to save a few pounds at manufacture? (i.e. the bead going up against the rim hook would be far more likely to seal?
What rims are you using, what tyres & size are you using? Are the rims definitely tubeless ready, as this sounds like an issue that you’d have with running tubeless with incompatible rims.
I’ve never had this issue with tubeless, both hooked and hookless. Probably points to a bad for with the rim, and / or too loose a tyre bead.
Maybe you need to re-wrap your tubeless tape with an extra layer?
Some tyres are prone to stretching at the bead, especially if removed and remounted often.
If you do have hookless rims, you should only be using hookless compatible tubeless tyres, which is a relatively small subset of all tubeless tyres. Giant for example publish a list of approved tyres they’ve tested with their rims as safe, and imo you’d be mad not to run something on that list.