Things always take longer to film there than it does in the US. I think part of it is due to more humane shoot days whereas in the US, they could go long and into the weekend.
A US production could, in theory, eke out 8 episodes in 8 weeks, although it usually takes a tad bit longer. A UK production can take months.
Season 3 of Bridgerton took 8 months to film because of its scale. Then they have to edit the show, finalize the production, translate the show and have all the international voice actors do the dubbing for the show.
