Notable items in those pictures;
1. Wires need to enter the box through suitable romex wire clamps. You can't just poke them through the holes.
2. It's sloppy. That makes it difficult to troubleshoot and repair.
3. Only one circuit per breaker / one wire under each breaker terminal clamp. Even though they are made to hold 2 wires, that is not allowed any more in most places.
4. Looks like Federal Pacific brand. Not manufactured anymore and their breakers have a reputation for not tripping properly when needed.
5. The cables must be supported within a certain distance after leaving the box. I believe it is 12". But I would have to review that.
6. Looks like 8AWG supply wire. Suitable for 40 amps per hot leg maximum. That doesn't mean the breakers can't add up to more amps. There is a calculation for that. Plus, you would rarely use every circuit at max capacity simultaneously anyway.
I would recommend increasing the supply to 100amp capacity and use a breaker panel with room for 16 circuits or more and it would then require a main breaker (no more than 6 disconnects per service). One central main breaker is a good idea just for safety and simplicity.
Then, fasten some 3/4" plywood to the wall between the breaker panel and the ceiling, full width of the panel. That gives you something to staple the cables to for support. Finally, use some vertical 2x4's, one on each side, and a plywood cover that can be screwed in place to build a plenum or box to protect the cables between the breaker panel and the ceiling. I would use PVC conduit components to protect the supply cable coming through the wall below the panel.