The same thing is happening to me and has done for about a year. Every time I update it, it’s expecting me to download the sim entirely. I have absolutely no add ons, I always kept the sim as is. I keep the sim updated, I keep my pc updated, all drives too. I can not for the life of me figure out why it does this and it’s incredibly off putting, I dread every update that comes out, each time it’s 115.03GB. Luckily I have 1GB speed internet but it does still take a while to download a file of that size, especially when you just want to get on and fly and instead your met with that monstrosity. I feel for people who have slow internet speeds having to put up with that tbh. I have this on the series s (I haven’t been able to buy the series x yet) and it never does this but on the pc, it’s a whole other issue and I do actually prefer it on pc, these updates are crazy though.