Simple little suggestion that I think would help with UV rolling be less of a money sink. What I'm proposing is a system where you can 'wishlist' UVs you want for any given piece of gear, all three slots, to allow a player to eventually create their idealized goal. Maybe reduce crown costs a bit too, 20k CR for a single variant can be fairly pricey, especially for solely F2P players.

Wishlisting would work as such: Whatever variant you wishlist on gear, for every time you roll for that UV and do not get it, the odds of rolling the specified UV(s) goes up on the next attempt. Odds reduced to base values once you get what you roll for, and the odds increase based on the level of UV you wish for. E.G: Wishlisting a CTR Low UV would have the chance of getting that UV go up faster, goes up noticeably slower for Very High, so on.

If I had to suggest possible prices for UV rolling after this too:

1 Variant: 15k CR
2 Variants: 60k CR
3 Variants: 170k CR

Or around those price ranges anyway.
I think a system like this or similar to this would give the average player more incentive to try rolling for UVs.