How to disable Wix default confirmation emails?

As we know, it is not possible to customize (much) the default emails that Wix sends to visitors who pay or book services online. Wix does however provide a way for us to send bespoke formatted emails to users via SendGrid (which is excellent) - however, our visitors always receive 2 mails - because we cannot disable the default email.

I am building a Wix site for a client who is in the Travel / Holiday industry. They want a website that can showcase their specialty holidays, and accept online bookings for those holidays.

I tried working with Wix-bookings / Wix-stores, but none of those can be coded to provide the correct booking experience, or the correct confirmation styles required.

Finally I resorted to coding a bespoke booking form process, which uses the Wix-pay API. With this method I can create a great looking booking & payment process - All good! (Except Wix sends its own email confirmation which displays my Wix Account email address, which has nothing to do with my client, and is totally confusing to my client’s customers - and I can’t find a way to disable it).
Come on Wix - we need to fix this!

I have sent several support requests to Wix, but they just pass the buck back, saying that they do not support custom code!

What can we do?? (Maybe abandon Wix and create a website with other tools?)