I tried figuring it out but I couldn't find a straight answer. Since there were easy to use RTMP plugins before OBS 32 I'll wait and see if the uploader responds or more options appear. Sharing streamkeys and logins is not for the faint of heart.
I used Sorayuki's Multiple RTMP Output 0.7.3.0 without any ill effects under OBS Studio 32.0.0, which I had used under 31.1.2.
As mentioned previously, this plugin, which is based on Sorayuki's plugin, requires that you have an account (possibly even paid) with the guy who published this plugin. Requiring an account to make multistreaming work at all itself caused me to check out. For additional context, I mean needing an account to make the infrastructure itself, not the accounts to stream to, like something like Kick, the former VStream, and other services. One such (particularly egregious) example is Streamlabs in this context, only in Streamlabs' case, you need not only an account, but a
paid account to even multistream
at all via something like Streamlabs Desktop.
I might consider using Aitum Multistream if it didn't lack some of the functions I need, which is the ability to synchronize the start and/or stop when you press "start stream" or having this ability via Websockets. Aitum does not seem to be interested in implementing either one.
So, I stick with the OG multiple RTMP output plugin by the aforementioned Sorayuki. Yes, it may be a little difficult to set up, but it has the one benefit I have a hard time saying no to: It actually works the way I need it to. I just want something I can recommend to my more computer-challenged fellow streamers.
--Katt. =^.^=