Your FLR visas were processed faster because they have a processing standards time of only 8 weeks.
On the other hand, ILR has a processing standards time of 6 months... so if you submitted everything on 23rd August, it could take until 23rd February 2024 to be processed.
Earlier this year, ILR was being processed much faster than normal (within a few weeks), but it seems like it's slowing down a bit now. In the past, the average ILR processing time has been around 4 months or so.