Where has UI Display Scale gone? [Partially-sighted user]

Hi,
I am part of a screen production / training organisation for disabled filmmakers and I am trying to work out how to natively increase the text size in the UI.
Apparently it is located in Preferences > User > UI Settings > Display Scale, but in my version of the software it is nowhere to be seen (see image)
We currently run Davinci Studio 19 on a Mac Mini M1. I thought it might be just we needed to upgrade, but from what I can tell, this feature was introduced in v18 at the latest.
I am part of a screen production / training organisation for disabled filmmakers and I am trying to work out how to natively increase the text size in the UI.
Apparently it is located in Preferences > User > UI Settings > Display Scale, but in my version of the software it is nowhere to be seen (see image)
We currently run Davinci Studio 19 on a Mac Mini M1. I thought it might be just we needed to upgrade, but from what I can tell, this feature was introduced in v18 at the latest.