Legal Liabilities/Left Job Started My Own Company

Left a job in construction after almost a decade. It's in United States, Utah. After working for a company for nearly a decade where I was originally promised ownership so I did an exorbant amount of work for them while making very little on salery to start. I was told about 3.5 years ago that offer was no longer available and I would not be getting any ownership unless I was to somehow come up with a huge amount of money. After threat of leaving I was offered a 6 figure salary so I stayed... For a while.

I began at that time to work towards starting my own company in the same trade. After a few long years and purchasing a property and finally recently finishing the building I'm about to start the business and have been threatened with a lawsuit if any of the previous places employees were to quit and leave to come work with me.

I do not have a none compete. None of their employees have none competes.

I do not have any intellectual property besides general construction prices for the area.

I do not plan to go after their accounts or employees but because of the way I treated the employees they want to come work with me and get away from the toxic environment where they are way underpaid and have zero benefits and want more for themselves and their families.

Should I be concerned or is this just an upset owner making pointless threats? The one today was something along the lines of he would sue for damages.

Honestly I just want to not stress about dealing with anything else and just move on from the toxic atmosphere any longer.

I don't know that it matters but I have a ridiculous amount of proof of some pretty illegal stuff the owners were pulling on the daily. Is leverage good or bad here? Should I ever mention the evidence? Could it help get them to stop calling and making threats? Or would/could it make things worse?

Side note owner and his wife are narcissistic psychopaths. Owner has been known to murder animals and stalk people with gps. He once was going to kill a cop with a sniper for sleeping with his wife and backed out last minute with finger on the trigger.

Seriously not stable people I'm dealing with but they have heeps of money for lawyers and could really make my life difficult.

Any help would seriously be amazing! Thank you in advance