Start Microsoft Windows, open up File Explorer, remove the ever-present 'Type' column (because if you're old school you'll have suffixes enabled), then go to Options and say 'Save this view format for ALL Explorer instances'.
Within an hour you'll have a Type column back in some new Explorer window, to inform you that your file.pdf is a PDF file type.
Any and every version of Microsoft Windows file explorer has done, and continues to do, this. It's hugely frustrating.
If you're using Gnome then it's a relatively easy (free, ethically sound, painless, etc) process to switch to, say, KDE, and enjoy pleasant file explorer/pickers.
If you're forced to use Microsoft Windows (say for work) then you are stuck with this particular broken toilet.