Text on Path stumped. Looks like a hybrid of Rainbow on the ends and Skew in the middle

Andrew, To add to what Monica has already suggested.

Here I also used Envelope.

I too did not like how the text looked especially the U in the center.

To tweak, I used Envelope Distort>Edit Contents.

You are still working with Live Text.

I added a space after st

I then Kerned the space between the letters FU. I used 100% instead of 0%

K

Can you please select it and show us the object inside the Layers panel? You have to click on the triangle to open the layer. This looks like you have applied an envelope.

Or is this something that you want to do?

A carefully constructed envelope might help. When the text is longer or shorter you might get in trouble:

You might want to take a look at the plugin FilterIT (not free)