I reserved unix.dev for the regular domain reservation price, not the crazy "premium domain" price because unix.dev was not part of the premium domain list. However, Google determined that no, unix.dev should be a premium domain, and "stole" the reservation from me (after I have already paid for it). They later added it to the premium domain list, and they asked me for $11k to keep the reservation. TBH, I expected to…
"Reservations" mean nothing. Google Domains is merely one of many registrars that have customers all vying for domains in the same namespace. A "reservation" just means that the registrar will make their best effort to attempt to get that domain for you at the specified price; it doesn't mean that some other registrar won't get it first, or that some other customer isn't willing to spend more and will get it on an earlier day of EAP.
Until the domain is actually created with you as the registrant, it isn't yours in any sense of the word. There are even registrars out there that will, upon acquiring a domain, auction it off amongst all of their customers who pre-registered it.