Okay, this is reasonable.It's always been believed by fandom that Spock was the first. The fact that there's an entire crew (including command staff) of Vulcans on the Intrepid seems to make this difficult but it's possible that these Vulcans were trained as part of the Vulcan fleet and transferred (at their existing ranks) across to Starfleet. Spock was the first because he was the first to enter Starfleet by going through the Academy.
I've repeatedly stated that I would like TOS sources only. Enterprise has nothing to do with TOS.And if you accept that T'Pol joined Starfleet in Enterprise then Spock can still be unique as the first Vulcan to go through Starfleet Academy even if he wasn't technically the first Vulcan in Starfleet.