The Rega Fono range is excellent, and I was pretty sure I’d read that the essential ingredients were also inside the Brio amp. However, if you search this forum, a Rega person is on record as saying the separate stage is better than the Brio or Elicit in-built stages.
I suggest you try for yourself, because if you detect no improvement the Fono is easy to sell on. I had an early Fono Mini for many years, and a later Fono II. When the time came both sold readily on eBay.