When you want one and when you can afford one seems to be a good idea.
Depends if you're a "I want it right now!" person or a "I want maximum value, so I'll wait for a good deal" person. I think I can work out which camp you are in.......
I've bought multiple secondhand bikes, both to ride and for spares donors, and almost all have been purchased between the end of September and the end of March, so essentially during the part of the year when the days are relatively short and the weather is less appealing.
My latest one was a 531 spares bike this month, and is my first purchase since February. I now have it and was delighted to find a pair of nearly new Schwalbes that would cost £40 fitted to a £20 bike! This obviously isn't in the "nearly new" category asked by the OP, but there are deals out there virus or no virus, and secondhand-wise the closer you are to the shortest darkest days the lower the prices.
For modern stuff, in normal circumstances it's around the model year change time, just like it is for cars. If a retailer has a lot of metal they want to shift to make way for next year's models, they tend to be a lot more reasonable on pricing. This year is not a normal new market though, due to supply constraints. Next year should be normal or even saturated, I would wait until autumn 2021 if buying new.