The insur just skyrocketed destroying my cash flow. 

Fannie/Freddie were nationalized in 2008 precisely so they could take the losses instead of the TBTF entities that couldn't take the losses without destroying the economy.

You can destroy everything, but LVP is pretty tough.

I don’t understand how that’s relevant when the tenant destroys the carpet.

I like the idea of the 4 plex because of the ability to house hack (and get residential loan interest rates), easier exit strategy than a commercial property (anyone can buy), and having multiple properties instead of all my eggs in one basket 20+ unit apartment (ie if a tornado destroys one property vs destroying my only property). 

I would send them notice of three violations. 1) lease says no pets...get rid of the cat before it destroys the property.2) stop smoking on the property or face eviction, offer to release any smokers from the lease.3) cure the insect infestation immediately.Inform them you will me making regular inspection visits and expect the issue to be resolved.Your other option, if you have no desire to inforce your lease is to tear it up and write a new one that you do intend to inforce.

Tenants always just destroy the carpet. basement

This is especially true in markets with wild asset value swings where their collateral can be destroyed in a few weeks.

If a pipe is leaking and destroying the home they may have no concern.

They destroy stuff.