While it’s possible the production got a head start if it kept the sets from the Enterprise used in Star Trek: Discovery Season 2, there’s definitely a healthy amount of post-production needed for effects in episodes that will undoubtedly take some time after production wraps.
If the Toronto website’s production dates are accurate and no delays halt production along the way, it looks like Star Trek: Strange New Worlds could be looking at a late-2021 release, but more realistically 2022.
For that reason, I wouldn’t imagine we’ll see the series arrive in 2021, but I’d love to be wrong and surprised.