How to restrict aspect ratio for android build

Project is using Unity 2019.4.40f. I have to get build for Android with fixed aspect ratio (16:9).
I’m trying to set aspect ratio via Project Settings window. But the “Up to” field doesn’t let me to set value lesser than 2.1. It lets to set value more 2.1 or more only. As I understand, I have to set “Up to” field value to 1.7777 for 16:9, but I can’t

What I’m doing wrong?
Thank you <3

Ok. I found this document

" It can not be set to a value lower than 1.86 which matches the aspect ratio of 16:9."
16:9 = 1.(7). How the hell it happens 1.86?

Anyone can tell me please how I to deal with this? I have application with UI resolution referenced to 1920x1080. The documentation says that 16:9 is 1.86 ratio :face_with_spiral_eyes: and because of that I see the sides of a game scene looking at me from behind of the app UI.

I used this solution:
https://stackoverflow.com/a/65224369/9043688
but it looks like a crunch.
Does anyone have a better approach?