I am not the salesman, but the 2-row mode ;-)

You are using the 2-row mode instead of the 3-row mode.
Therefore, the vertical space in TM FX is smaller!

If you switch to 3-row mode, you will see the layout presets menu. Then you will also see the ‘Sub’ button.

You can also stay in 2-row mode, but then you have to collapse the ‘Groups’ menu (click on the little triangle).

For a while, I thought it wasn't implemented, but when I saw your screenshot, I remembered that you have to collapse a window to create some vertical space to see any remaining menus.

The problem for you was not being able to see the Layout Presets menu in 2-row mode because the TM FX window stops right at the end of the Groups menu, and you can't see the next one yet.

Pretty much until I started this thread, I've always used 3-Row mode at 100% zoom. I only tried 2-row when I zooomed to 135% and it was too tall to fit on my screen. That sent me down the rabbit hole of trying to solve my problem and discovering new ones. With my OG Babyface, I do not have Layout Presets, even in 3-row mode. However, when I switch my TM to the FF800, I DO have Layout Presets. So... I guess I have it...?

You are using the 2-row mode instead of the 3-row mode.
Therefore, the vertical space in TM FX is smaller!

If you switch to 3-row mode, you will see the layout presets menu. Then you will also see the ‘Sub’ button.

You can also stay in 2-row mode, but then you have to collapse the ‘Groups’ menu (click on the little triangle).

For a while, I thought it wasn't implemented, but when I saw your screenshot, I remembered that you have to collapse a window to create some vertical space to see any remaining menus.

The problem for you was not being able to see the Layout Presets menu in 2-row mode because the TM FX window stops right at the end of the Groups menu, and you can't see the next one yet.

Seems it is time for a HW upgrade

Now there's a salesman.

I know this is not an "issue" for anyone else, but I've just restarted my computer a few times while trying to see if the Layout Presets pop up (before y'all responded), and somehow this blank space in my TM gets bigger after every restart. No lie. This is now the entirety of my screen.
https://imgur.com/gHz3xRy

Okay new issue... I don't have the Layout Presets option. I'm on Version 1.97. I just watched a video from the RME YouTube page that was posted 5 years ago and his TM has it. I have never seen that option. That area is just blank space on mine. Is that because I'm on the original Babyface and not the Pro?

Correct.
I just did test with offline device and indeed that SUB button feature is not available in Totalmix Babyface but Babyface Pro

https://rme-audio.de/downloads/fut_usb_win.zip

In the new Totalmix there is a button SUB under Layout Presets.
This could be interesting for you, it let all channels disappear who are not involved in the mixing scenario.
Especially useful for Madi and Dante.

Okay new issue... I don't have the Layout Presets option. I'm on Version 1.97. I just watched a video from the RME YouTube page that was posted 5 years ago and his TM has it. I have never seen that option. That area is just blank space on mine. Is that because I'm on the original Babyface and not the Pro?

In the new Totalmix there is a button SUB under Layout Presets.
This could be interesting for you, it let all channels disappear who are not involved in the mixing scenario.
Especially useful for Madi and Dante.

I think half of my reply from my last post somehow didn't post. 
When I open a new window and try 2-row, it combines the software playback and hardware inputs on the top row. But in my original window on 2-row, it combines my software playback and hardware outputs on the bottom row. Wild stuff.

I'll try this. Sounds like it might be an option for me.

The point is  that you are the only one who thinks this is an issue. The 'gap' is not an issue but necessary free space, and the moment you use mono channels or open Settings panel or the EQ the gap is gone...

Fair enough. Maybe I'm the only one who cares about the management of screen real estate and minimizing necessary button clicks, and if so, my bad. Everyone keep on keepin' on.

I didn't even know you could open a second window!

I’m guessing you don’t have this same issue in TM? Your answers lead me to believe that this is not something you’ve ever seen or heard of.

The point is  that you are the only one who thinks this is an issue. The 'gap' is not an issue but necessary free space, and the moment you use mono channels or open Settings panel or the EQ the gap is gone...