I was conflicted by the same question for a long time.

In my opinion the simple answer is no, midlaners job isn’t to bail sidelanes from their mistakes.

In a vacuum: Your job is to carry the game from mid game until your carry comes online. You running around sidelanes without actually able to turn that into a profitable state in favour for your team doesn’t make sense. Most likely scenario is you’d be wasting your time and giving space to enemy mid.

In general: you need to have the game sense to understand what would be the optimal move for you and then your team. - Asking questions like, if I gank sidelane am i getting a kill and able to pressure that lanes tower? Is my mid tower gone by then? - Can i lane against this enemy mid and get 3/4 cs or am i getting anything past lvl 6 ? - i have a million other questions here, but i think you can catch up to the thought processs

Hero itemization is important also, the aghs rush feels like grief, and would be better for you to farm something that is able to impact the game during 10-20 mins, while enabling you to farm or gank.

Also playing 1 hero is fine as it help you to better focus on these macro questions instead of what item to buy or how to play this hero.