Is it more moral to allocate goods to the people who are willing to pay the most for them, or to the people who have good scalping bots/happen to get lucky

They could easily do both.

They could sell the first few for more and settle down to their normal price after a time.

There isn't sustainable demand for a $300 steam controller, that's why they didn't price it there, not because they didn't want to sell for a huge profit. Ther is, however, a much smaller market of people who will pay a premium to be first, hence the resellers.

I'm not performing any sort of moral judgement here, I'm using 'underpriced' to describe a good that is sold below its equilibrium pricetag. Companies are free to do what they like, but lower prices will always lead to scenarios like this, where these go out of stock before demand is satisfied, and this discrepancy is what allows scalpers to exist in the first place.

then how can scalpers sell them for more money than the original asking price? also see my other comment cf use of the term and equilibrium price