Many fastigiate trees split in this way all the time because the branching happens in very acute angles and this creates a weak point.
Asimina and mulberry aren't good for sidewalks. Asimina is too short, parse and wide and spreads from the root. Mulberry is a tall tree, too big and too wide. Both made the soil slippery and a mess by fruits and leaves.
A possible replacement could be young american hornbeam that can be pruned narrow for a long time before it opens wide. there is not a lot of candidates for a narrow sidewalk. Landscapers deal with this problems and try to fix it all the time.
The white - look for Shahtoot - has long and slim fruit, with a much more delicate flavour. Can recommend.
Birds left ours alone for a decade, but once they discovered the fruit, they live in there from November through December (AU) relentlessly picking off the ripening ends of each fruit.
A bigger concern with mulberry trees may be their allergenic properties.
White has a cultivar named Morus alba 'Fruitless' that is often used in cities. You can ask for it if you want a tree that will not stain the pavement.
The normal tree with fruits is a birds magneto but is a medium-big tree. Use it if you can provide the space necessary.
https://www.thefruitexplorers.com/blog/2021/03/29/defenseofb...
Edit After Downvote: I get it - They were a major nuisance to you. Lanternflys weren't a one time thing. This has happened before - remember stink bugs? This has happened many times and it is going to get worse. Please don't shoot the messenger.
But Tree of Heaven is also an invasive species, native to China like the SLF; it's their favorite host plant. The SLF invasion can be very "spotty". If I eliminate the stand of Tree of Heaven from my yard, the SLF will probably go elsewhere. I don't use pesticides or herbicides of any sort... just some copper fungicide for my fruit trees.
And when species like this thrive in the native environment?