Not to push back too hard on this, but creating tickets instantly isn't that difficult to accomplish.
In Exchange, create:
a Contact for otrs@otrs.local
a Send Connector for otrs.local that points the smarthost to be the otrs server
and forward support@yourdomain to the otrs@otrs.local contact (Mail Flow Settings, Delivery).
For OTRS on-premises Exchange, this doesn't require opening up any Internet-facing firewall ports at all.
While it's beyond this scope to cover all possibilities, email forwarding + MX record of some sort / smarthost usually isn't outside the realm of workable.
Plus, you know, instant tickets and not having to ask a question like "how many emails can I fetch at a time?" The answer would be, of course, all of them.