Sorry, I meant to reply some time ago after watching the recording, but must've closed the window without sending the message!
The main solo content in the game rn is playing the arena modes against bots. All the modes can be played with bots except for Survival and Boss battles (which are pve) and football.
Bot difficulty and number can be changed in the mode settings menu. Otherwise, a default number of bots are used according to the map size.
Thank you so much for sending me the recording; I now realize that the bots might not be clear since they are a relatively new addition. I'll highlight that feature more since it is the main part of the game for the foreseeable future.