I read time and time again that "FRFR wont get amp in the room sound" - but I'm just not sure I agree. Maybe its my particular "FRFR" - but I've found that I can get close enough for my purposes.
I see it as needing 3 main things if you want FRFR to feel "amp in the room":
I would guess most people associate "amp in the room" with "loud".
Specifically meaning, 5" Studio monitors on stands simply wont recreate the effect like a guitar cab (or FRFR) on the ground moving air.
Good cab IR that matches whatever you're "expecting"
There are a million companies making them now. Take your pick
Personally, I use a single Orange IR from OwnHammer on almost EVERYTHING now...just because thats the cab I was most "used to"
You can probably do just fine with the built in Cab blocks - I just have no interest in exploring since I found a set of IRs I'm very happy with.
That is, Parallel EQ with what feels like an agressive high pass and low pass
The IR does a lot of work here - but its still my experience that an FRFR will be a little "boomier" low, and still project WAY more high frequencies.
Anything from a high pass up to 130hz and low pass as low as 4k or as high as 14k. Maybe use the P-EQ to scoop a little 4-6k?
Of course, this is all done with the intent of emulating an "amp in the room". I have little idea how it would work if I ran this exact patch FOH, but I don't think it would be disastrous by any stretch. (After all, at worst its an unmic'd cab sound?).
I'm able to make myself happy and shake the walls just the same as I used to with amp and cabs... only with the added perk of being able to play at talking volume and still enjoy the experience. (I never liked my analog / tube stuff quiet).
I don't miss having an analog amp and cab anymore. Occasionally I'll think "that would be fun!" - but quickly realize I wont use it much, or it would be a passing novelty I end up selling again eventually anyway. I already made the change once when I got the Helix.