Seriously struggling with key changes

Hello again, everyone!

It’s been a while since I’ve posted a thread asking about Key Changes, and just when I’m finally starting to understand them, I come across a tab that just stomps me.

Here is the culprit tab.

In the verse, the key is in C Maj. The prog starts with a V and literally never uses the I Chord. It does, however make a lot of use of borrowed chords; specifically the III from min, and the VII from phrygian. It only uses the I scale degree in the melody at the VERY END of the progression. Where I get lost is the key change to F#maj.

The more I look at the progression, I start to feel like there are some inconsistencies in the tab. Surely there’s a better way to notate this progression. The initial submission of the verse seemed to make more sense in the fact the key was Gmaj as opposed to Cmaj, allowing the beginning to start with a I chord as opposed to the V. But it still doesn’t explain how this particular key change managed to work. Suggestions or comments?

If there are any theory vets out there, I challenge you to set this progression up in a more understandable way.