Cards that are three months away often only have a few official fights scheduled. Is normal.
I went looking into this, since I can't sleep and I'm pretty used to 3 months being kind of the default consideration for a camp preparation and length.
We're 81 days out from the event.
I went looking into the events from last year, trying to find one that had as few scrapped fights as possible, and ironically came to UFC 286, which was also in England. Although there were some replacements, no fights on this card were scrapped. It took place 3/18/2023. 81 days before that event would have been 12/27/2022
Edwards - Usman : Announced 1/14/23 (63 days)
Gaethje - Fiziev : Announced 1/14/23 (63 days)
Nelson -
D-Rod Barberena : Announced 1/13/23 (64 days)
Maia - O'Neill : Announced 1/6/23 (71 days)
Vettori - Dolidze : Announced 12/15/22 (93 days)
Shore - Amirkhani : Announced 1/19/23 (58 days)
Duncan -
Figlak Morales : Announced 1/11/23 (66 days)
Ashmouz - Patterson : Announced 1/22/23 (55 days)
Mokaev - Filho : Announced 1/16/23 (61 days)
Murphy -
Wood Santos : Announced 1/6/23 (71 days)
Duncan - Todorovic : Announced 1/20/23 (57 days)
Hadley - Gordon : Announced 12/23/22 (85 days)
Wood - Carolina : Announced 12/17/22 (91 days)
Herbert - Klein : Announced 1/6/23 (71 days)
Hardy - Miller Announced 1/13/23 (64 days)
So I guess I'm surprised to find that most fights are announced just over 68 days before the event (according to this tiny sample size). Though this card did still have 3 fights by this time, and 304 isn't affected by the UFC's usual end of the year, beginning of next year pause that they often do (bookings are often kinda slim in December as you can see, and most fights into the new year wait until the year starts). So even with the renewed expectations, I'd still think 304 should have more bouts official by now.