Apple just released the versions macOS 10.15.4 beta and tvOS 5 beta 13.4 for developers. In this case and as with the previous beta versions for developers, these are versions with improvements in performance and system stability.
In principle we do not see that these new versions add major changes compared to the previous beta versions and we are already very close to the final version of macOS and the rest of the operating systems, so the most notable changes have already arrived in the first betas and now it's about stabilizing the version.
The Cupertino company does not stop and already offers the possibility of updating to new betas as long as you are an authorized developer. At the moment public beta versions are not available (while we are writing this news) but it is most likely that they will end up arriving in the next few hours as long as there is no problem in the developer versions.