I made a post on these here, and this is u/MichaelMcRooney ‘s response.
K. Gonna have a chat. The mobile version doesn't have multiple lines because it negatively affects performance. We're looking into ways to give more options to optionally add more lines in the future for people with more powerful devices or people willing to take the performance hit, but other things are higher priority atm. :/
But I hope we can finally get it, or be able to turn it on/off.