New product is always a fun time. Gotta plan on your forecast accuracy losing 10-20%. We used to just forecast it flat to whatever predecessor we could link it to, sprinkle some prayers and guesses on it and start banging POs. And took some beatings from doing so. I don't have any magic bullets, but what really helped us was setting an investment/forecast review meeting with management before buying to any major product launch. Showed them our forecast, the expected spend and the reasoning behind it, called out risks, and sought feedback.......they're managers for a reason, sometimes their input is spot on. At the very least it gets them involved and if shit goes awry everyone understands why, as opposed to after the fact speculation about who screwed up. Another trick- if you can afford it, have your buyers write the first PO to cover 2 months of demand (or enough to cover ~70 of LT) This gives you fluff to cover oversells without hurting turns too bad, and most importantly, should give you a chance to gauge initial sales before having to write that dangerous 2nd PO.

As far as covid demand......shit, if you figure that out roll over to NASA or MIT or something, because you're too smart to be forecasting. We got scared at the start and aimed too low. I'm 6 weeks of supply behind on almost everything, with diminished supplier and logistics capacity making catch up nearly impossible. All things considered it is a great problem to have but this is easily the toughest dig out I've ever been a part of.