Settings layout in Teams channels for Posts/Threads

Hello,
Microsoft has rolled out the new chat layout in Teams channels.
I've seen the associated documentation and its arguments in favor of this feature, but several users in my organization still want to use the classic layout (as a post for each message) rather than threaded layouts, as this is better suited to their business.

I found several documents indicating that the layout can be set when the channel is created or changed later (https://adoption.microsoft.com/files/microsoft-teams/Threads-layout-in-Microsoft-Teams-channels.pdf). However, I can't find this setting on either the web version or the heavy client (https://cxcs.microsoft.net/static/public/messagecenter/neutral/01e0fd3a-ddc6-4db3-b411-100f86febf85/5fdfc3d6287306c4fc54112660c2fb9ed86d4f94.png).
Currently, each new Teams or channel only presents a Thread layout, and there's no way to choose.

Do you have any information on how to choose a layout?

Is this a setting that needs to be enabled in the Teams admin console?

Thanks in advance.