> Unfortunately, eBay uses emoji in the subject lines for a bunch of their transactional email, e.g. "<U+1F4E6>ORDER DELIVERED".

Don't really use G-mail (I personally use proton) so I am not sure but can't special exceptions be made for E-bay if that's the case?

GMail doesn't currently have any feature to do that kind of filtering.

Which is why they go to spam so often.