Installing the 95/98 GTK theme by B00merang is one of the first things I do after a fresh installation of Linux Mint.
I do try other themes once in a blue moon. But I soon realise it is a downgrade and revert back. The last theme I tried was the Arc theme back in mid-late 2010s.
My biggest hurtle is why i can't see files as thumbnails when picking a file to open or save. It works for file library but the file picker won't show images as thumbnails. Only a list view with tiny thumbnails that sra too small to see the actual image