Well, it's not all that bad. You'll get FSD 11.4.9. Same as I've got, since the 12.x magic fairy hasn't dipped its wand at me yet. (I'm kind of waiting around, seeing as the car's on 2023.44.30.8.)
And 11.4.9 is not to be sneezed at. I've used it commuting around NJ since it came out and have made several trips back and forth to the Boston area since the beginning of the year. The 11.4.9 stack is very good on highways (and is currently used on the 12.x releases for that purpose) and it's not half-bad on local roads. I'd guess at, what, 5 interventions in 10 miles, on average, when it does silly things. But with well-marked roads and nothing strange going on with crashed cars, cones in the middle of roads, and unprotected left turns on double-wide not-marked-well lanes, the car does OK. I've made it 30 miles or so with it changing lanes, making turns, and all that jazz.
One does have to supervise, local roads or not: FSD is still a beta. But it's not like the old days that, when one ponied up one's FSD payment, one might have to wait months for the FSD release load line to match up with the Everybody Else load line. Nowadays, one gets the FSD stuff right off.
Finally: If one hangs out on the FSD-b main thread, one will note that there's been Lots of Fun of the negative kind on both 12.2.1 and 12.3. At this time, it appears that Tesla is taking a slow, safety-first approach to this new software. My guess is that they're planning to go mainstream, non-beta. Based upon tweets from Elon and the development team, their rough guess is that they may be done in late April or early May. At which point, if you're still running FSD, you'll get the new, shiny stuff with all the bells and whistles as they upgrade the main release load line to whatever 12.x they'll have gotten up to.