Back OT, 6/8 is a kludge but easily done following many of the suggestions posted here.

As for notation, export the MIDI to most notation apps and fix it there. Finale/Dorico/Sibelius all handle this easily. MuseScore, not so much but I was told at NAMM that the upcoming v. 4.5 will be much better (long talk with MuseGroup about this and other issues last week in Anaheim).

The reason that Real Band never existed on the Mac is because GarageBand is free (since 2012, I think). PG Music has considered RB for Mac redundant—not sure they're wrong but I am long past caring—don't see RB bringing anything to the table that I'm not doing now.

As for myself, I start a lot of projects in BIAB but finish most in Digital Performer where I can edit my performances to the gnat's whisker if I so please. This has become more difficult since BIAB is not Apple Silicon Native and no longer plays well with other apps that are—this got worse with 2024. But… BIAB still saves me a ton of time which is why I use and like it.

I'd much rather see AS Native for 2025 than 6/8 & 12/8 be added—but I do think it's long past time.

BIAB 2024 Audiophile Mac
24Core/60CoreGPU M2 MacStudioUltra/8TB/192GB Sequoia, M1 MBAir, 2012 MBP
Digital Performer11, LogicPro, Finale27/Dorico/Encore/SmartScorePro64/Notion6 /Overture5