I've beaten it twice, and the first time I was quite a bit of the way through before even discovering the mechanic of making buildings. I'm wondering if there's some problem where the game runs differently on different systems, so we're facing radically different difficulties.
I would have to assume so because I don't believe that would be possible against what I faced, but I also haven't heard of difficulty scaling (of all things) being different across different systems (Windows 11, Chrome, to be clear)
I'd start losing goblins by about the third battle, of course they don't respawn so losing more than 1 per battle means you're weaker than how you went into the fight.
Even with full perks, pyromancers, 30 odd barracks and high level spells - fights quickly became completely one sided (for them) and unwinnable in the traditional sense