A suggestion about folders would be the possibility to add other folders in the item "Excluded Chats". On this case, all contacts, groups and channels in that folder added in "Excluded Chats" would not appear in the folder being created or edited.
Yes, I see the prompt "Choose chats and types of chats that will not appear in this folder". But it seems to me that this is not what you need. I do not use the general categories "Contacts", "Non-Contacts", "Groups", "Channels" and "Bots" to add folders to folders. And when there are hundreds of chats / groups / channels / bots (with dozens of actual ones), and ten folders are too few for me, I see no reason to add a list of exceptions to the description of each folder (if I understood the meaning of this list correctly). And we are talking about something else - how, in relation to a particular chat, quickly determine its belonging to folders. Moreover, now only in the Android application there is an opportunity to see the list of folders in which the chat is NOT included.
I suggest to manage chat / group / channel / bot folders right in info tab too. As example I can have a new work contact or group, in order to put it in the folder I need to go to settings, instead of open its info and mark folder it belongs to.