Samsung has released the second Android 10 One UI 2.0 beta update for the Galaxy S10 5G. The 5G Galaxy S10 model was not included in the beta program for the regular Galaxy S10 models but received a separate beta program over in South Korea. The Galaxy S10e, S10, and S10+ received their second Android 10 beta update around the same time the Galaxy S10 5G beta program was kicked off, and the 5G model is now getting a new beta build as well.
The Galaxy S10 5G's second Android 10 beta doesn't seem to have the same changelog as the one for the LTE models, although we can't be fully sure as translation from Korean is something neither Google nor Bixby handle very well. The new build has quite a few bug fixes, though, and if you own a Galaxy S10 5G, you should get it right away by going into the Settings » Software update menu on the phone and tapping Download and install. It comes with build number G977NKSU2ZSK3 and is a 552 MB download.
As for when the next beta update for the Galaxy S10e, Galaxy S10, and Galaxy S10+ will be released, your guess is as good as ours. We're also waiting on Samsung to expand the Android 10 beta for the Galaxy Note 10 and Note 10+ to more markets. The Note 10 beta debuted in Germany on October 28 (after a false start on October 25) and is yet to be launched even in the US or South Korea, so it remains to be when countries like India, France, Spain, Poland, and the UK will get it.
Thanks for the tip, @jrwut!