helloworldsimcity

If you got a big city and a big region, it's gonna take a long time to save and load the region. Have you tried putting all graphics settings to low and unchecked all boxes?

You need a commercial zone that's big enough to fit the building.

You can make a area that's away and not connected to your main living zone and destroy all the buildings that have wealth levels you don't want there. There's no mod however for your problem.

Make a island, subway, or ferry.

Or make a trash city and make a neighbour deal with it.