Samsung Galaxy S20 series is already receiving the April security update
Samsung has recently had an interesting track record regarding Android security updates, which have at times come out before Google had a chance to release them for its Pixels.
The situation is the same this time around. The Galaxy S20 family is now receiving an update that includes the April 2020 security patch level. So far the rollout is happening in Taiwan and Hong Kong, with Korean units set to receive it very soon.
Aside from the new security fixes, the new software also packs some general camera improvements. The build number is G98x0ZHU1ATCT, where "x" is to be a different digit according to which of the three S20 iterations you have.
Since the models sold in this part of Asia are different than the ones that are up for grabs in other markets, like Europe and the US, keep in mind that the updates they receive may be different to those in other places. So while the April security patch will probably make it to every S20 out there pretty soon, this specific update may not. About a week ago, international models already received an update to fix camera issues, for example.