@ZeldaPrissy I'm so sorry for your frustration! From all of the links & info mentioned in this thread about 'reasons why' this message would pop up for some folks & in some situations, I've learned some things myself.
Personally, I've even found that there were times where I added a debug item while building a home that doesn't actually 'stick' (like certain debug items that are attached to an interaction), and I've been confused about why it was removed when I placed the home in a new location. I've also found that there are some here-and-there items that were bonus content items that I never qualified for (for instance early purchase items, 'gift' items from before I had a pack, etc.) that I was confused about 'why they were removed' when I placed a lot or Sim/household... since I owned all packs. Just to add to the list of confusing reasons, I thought I would mention those, as I don't think I did before.
Anyway, whichever are your particular reasons for the 'removed items' message, I hope things clear up for you, and that there will be some workaround methods that you find through the posts and information in this thread. Also, there are some great recommendations that EuphorialQueen and Crinrict made in the thread you shared.
Thank you for your patience and trying things and reading through the information. And, again, I'm sorry for your frustration.