Put the following code inside a localscript and put the localscript inside StarterPlayerScripts (in StarterPlayer)
local Chat = game:GetService("Chat")
local function setUpChatWindow()
return { BubbleChatEnabled = true }
end
Chat:RegisterChatCallback(Enum.ChatCallbackType.OnCreatingChatWindow, setUpChatWindow)

3 comments
As you know, roblox has removed bubble chat and this is the only way to enable it.
Link to post: https://devforum.roblox.com/t/removing-chat-type-avatar-appearance-override-settings/188227
You're supposed to post a question, not a suggestion