Most of my gaming is done on PC, but I bought a base PS4 last year only to play MLB the Show since a baseball simulation doesn't exist on any other platform. Also, I'm an MLB the Show content creator via YouTube/Twitch.

Now, historically, I've been an Xbox guy when it comes to consoles in the past. There are rumors that MLB the Show 21 will be on Xbox next year and cross-platform with PlayStation. If this is indeed true, I will go the Xbox route.

Here's my dilemma: For the sake of the quality of my content, would I benefit from upgrading at LAUNCH from a base PS4 to a PS5? I'd still be playing the 2020 PS4 version of MLB until the 21 version on the PS5 comes out in March. Or would it be better for me to wait it out and then pick up a next-gen console when the new game comes out Spring 2021? I'm really just concerned about the visual quality of the game when it comes to producing content as I'm trying to grow my brand.

Right now I'm leaning towards waiting it out, unless there's something I'm missing that you all could point out.

Yeah, what he said. If you can afford to wait, I would wait. Even if its just to let some of the bugs and growing pains with launch work out.

I've decided to wait it out until Spring and pick up a Series X. Thanks for the advice all!

aka_STEVE_b
I'd wait it out. 
First, the game might get delayed , as many others have been due to Covid.
Secondly,  the pricing of the consoles may have better sales by then and/ or you'll be getting a refined manufacturing version that so often happens 6 months+ from the initial hardware launches...

Concur with this.

Even if you were able to get a PS5, I'd still wait it out--as others have suggested.
 
Personally, I haven't seen anything too exciting on the console front outside of super-fast SSDs, and I'd rather put that 500 bucks toward a new rig. Then there's the old backlog...which will have me playing on my Pro and current box through the end of next year--or until I can afford a new build. ;)