LibreOffice is probably about 10% of the size of MS Office these days...
As for instructions/support: Changes between subsequent versions are minor. There was a versioning scheme change recently, so you may be thinking "Oh, LibreOffice 7.3 vs 24.8, very different" - no, mostly the same thing, it's just that 24.8 came out in 2024, in August. Also, there is ask.libreoffice.org #libreoffice on irc.libera.chat , and there are Telegram and Matrix channels... so just ask.
But it's true that with 0.1%-0.5% or so of the budget MS Office gets, it's difficult to keep all of the materials fully up-to-date.
Don’t forget I was replying to a person who is using Office 2003 and not paying as they probably paid their once 20 years ago for license and also don’t have any new features.
Last time I tried it (maybe 20 years ago?) there were fidelity issues (documents didn't display exactly identical to authentic Word), and some differences in minor features.
I should probably give it another whirl, although I'm really happy with 2003.
The fidelity issues are still there if you are loading Microsoft formats into LO. All the Microsoft format specificions are a insanely long, complex messes that even Microsoft doesn't follow, so I suspect that will always be so. But Office now read/writes ODF files, so you can ask it to convert into something LO is the authority on. That also means you can send an office user an ODF file, and expect it to be displayed sensibly.
So the friction is still there, but it's a lot less now.