Unable to change Meeting window view from Dual window to Single window with tabs

I don't want Zoom to be opening 3 different windows for single meeting (one for zoom app home, other for meeting participants, other for screen share). Instead it would be comfortable for me to use tabs. I see setting under `Meetings & Webinars`  called `Display > Meeting Windows View` which is set to `Dual Window` but I could not change it to `Single Window with tabs` because that section is blocked out. Also, Zoom documentation to fix the issue seem to be old which suggest change a non-existent setting under General tab

Why is this blocked out? Is this the right way to achieve what I want?

Version: 6.4.12 (56699)

OS: Mac OS

I am using dual monitor but nothing changes even when second monitor is disconnected