What puzzles you is the core of each campaign and highly depends on the layout of it.
You gotta try and if you fail, try a different approach.

Saving the game from time to time helps avoiding catastrophic failures without having to start from the beginning.

I haven’t and truth be told I wasn’t even aware of it.
Thank you for your support in wasting some more time with HOMM 🤗

Heroes of Might and Magic III, although I don’t think the game is bad.
What’s bad is that there’s really nothing new to it and yet from time to time I sink lots of hours into a new campaign.
It’s a kind of time machine bringing me back to more innocent times…
For the same reasons I need to beat some computer opponents in Broodwar on Big Game Hunters every once in a while.

Me and my Steam Deck approve.

…and failed to save anything at all.

You expect Nazis and their sympathizers to have a brain and form coherent sentences, huh?
I fear, there are at least some who do and those are even more dangerous than the typical braindead Nazi.