They are not "Drop-in replacements" and are not intended to be. They fill the same ecological niche, but are parallel products, not a copy. Quite different under the hood.

I use LibreOffice daily (mostly Writer, but also Calc) to run my small consulting business. I compile reports which can be quite long and complex including front matter sections, table of contents, index of tables and multiple levels of headers. Lots of internal referencing and footnotes as well. I have also used it in windows within a company where everyone else was using Word, without any more issues than the Word users were having. The main problem with Word documents is the build-up of auto-generated "styles" and people's use of direct formatting for everything. This leads to inconsistencies. With LibreOffice, the use of styles is much more integrated at all levels than in Word and learning to use them properly is a game changer. I have found the direct generation of PDF from Libreoffice to produce a better result. I like Calc better than Excel but they use different but similar macro languages so Excel macros are not always directly compatible in Calc.

Remember that on linux you can change most things, including installing a different software manager GUI such as gnome software, e.g. sudo apt install gnome-software .

I just do updates from the terminal, but I still use pop shop for finding and installing software.

Disclaimer: I haven't used gnome software, and there are others available.