I have never heard any native German say "Bauer" for builder. "Bauer" is definitively Farmer unless it is used as a suffix.

Yes, it's not the common usage, but it's still a legit meaning according to the dictionary.

But the relevant point here is, that Youtuber has a channel about building and testing Hardware. I don't know whether he has any relation to farming, but considering the content I would think his intention was a wordplay on building, not farming.

I agree.