Hi Jill,
I agree with what David has said regarding the back-ups and would add my understanding is Lightroom stores a 'sidecar' file with all the instructions for the edits, rather than copies of images after each edit. The back-ups of the catalogue do mount up but by far the the biggest files in my experience are the preview files shown in this screenshot:
Screenshot 2022-11-26 at 21.28.50.png
This can be managed by the type of preview you have enabled but clearly they are big files. (Note this is a fairly new catalogue - they get much bigger over time.)
You can delete these at any time to gain space and it will rebuild previews as and when required. If, like me, you tend to import a lot of images into LR then whittle them down to those worth doing a bit of work on it makes sense to delete the preview files afterwards so you only retain/generate the relevant ones.
Hope this is helpful
Simon