True but I have no doubt that production is significantly scaled back from what it used to be
I'm not so sure about that...
I've just went back and tried to count all the names that were listed in the credits for this year's Celebrity Big Brother in Germany, which runs for 17 days* and included every single person that worked on the show in some capacity. I've counted 388 names and did not count the names listed as "With thanks to", which would have taken the number over 400.
It also doesn't include third party for catering or security (because those were only companies listed), but it does include a few people who were credited for being CEO of the production company or the TV channel. Some of them were involved in construction of the set and probably didn't work for the show for its full run. But I don't think I can exclude so many positions that the number would actually be below 100.
And for comparison: I also tried and count the names listed on ITV's version. There are around 200 people listed in the credits of one of the daily shows. I haven't compared the names to other daily shows and don't know if it they just list all editors etc. that worked on this specific episode or on the daily in general. But the 200 does not include people working on Late & Live or the eviction shows as it doesn't list AJ, Will or any styling crew etc.
And I have not counted the names for those shows, but sources say 350 people working on Australian Survivor and Julia Morris claimed 500 people working on I'm a Celebrity. So I really can't see Big Brother do it with less than 100. Otherwise, they might want to sell their knowledge on how to do that to TV execs around the world that would then likely overpay for their versions.
(* you could probably make it 20 days, if you include the influencer web edition that run for 3 days shortly afterwards and probably used some members of the same team)
I’m positive the thick of production will be handled on site if only due to the sheer quantity of footage alone.
There are lots of shows that handle the whole "film there, edit it somewhere else later" just fine. You log things and you use AI to help you track things down. It's not that complicated. And it's really not that hard to access data in the cloud. It's not even that much of a ridiculous amount of data saved. I know from several other versions in Europe and North America that they don't record the footage from all cameras but just a few... and then they use separate, somewhat pre-selected recordings to put the show together and only go back to the "full" archive if necessary.
While I haven't read anything in that regards about the Australian production, I highly doubt that they'll do it completely differently from their European and American counterparts.