Uninstall and reinstall Lightroom

The size of the Lightroom Classic Catalog will grow quite slowly; however, continually adding more images to the same drive will cause it to run out of space much faster. I would leave the LRC programs and Catalog on your fastest drive, and move all images to another drive, perhaps a large external Hard Drive.

Many documents on the Internet on cleaning up Windows 10, Getting rid of junk, getting rid of leftovers, getting rid of unneeded programs (watch out for old versions that did not get deleted by the way)

For example:

https://www.windowscentral.com/best-ways-to-free-hard-drive-space-windows-10

(in that site, notice the next button, lots of pages)

• A upgrade of LrC should not be a big hit, perhaps the previous version did not get removed?
• A major Windows upgrade can leave behind files, such as the previous OS (in case you need to revert) (this is mentioned in web pages)
• Temp files, and Recycle files could be adding up (keep it clean)
• CACHE files (other than paging file) might not be clearing out after use
• Lots of documents on C?
• Lots of Download files no longer needed on C?
• etc.

Oh, and where do you keep your LrC catalog backup? And your photo backup(s)? C? I would keep them on a different drive, but not the drive your catalog or photos are on, probably an external one or two (or an internal if you can add another one)

P.S. Yes the LrC program can be installed to other than C, but not all of it, and might not be worth the trouble, and might need to be mitigated at each and every update or upgrade. Capability is in the Adobe Creative Cloud Desktop App (ACCDA). In ACCDA preferences.

In addition to the good advice from @KR Seals , your photos take up most of the space, and usually this is a lot more space than the application. I would move the photos from C (if that's where they are) to a different drive, rather than move LrC to a different drive. Instructions (scroll down to Part 2 — Updating Folder Location)

Where is all your data located, including photo image files? It's much easier to put all your data on 😧 than try to install programs there.

Also, What size is your C: drive. In Windows, it pretty easy to install a new and much larger drive (SSd prefered) for C: drive. Your C: drive should have at least 20-25% free for proper Windows operation.