Many Microsoft Flight Simulator 2020 add-ons that have not yet been tested and officially released for MSFS 2024 may already work.
Here’s how you can install them in the new simulator and test them for yourself, including a trick for Orbx Central’s client, which would usually require you to have both simulators installed, but the requirement can be bypassed.
Source: N4G PC Here's How to Use Your MSFS 2020 Addons in Microsoft Flight Simulator 2024, Including Orbx Central