Loyalty...

Before, during and after his presidency, Donald J. Trump demanded loyalty from everyone surrounding him. He still does. I've seen a few videos of his former attorney Michael Cohen, who described it and made reference to loyalty like the mafia. Former deputy press secretary Sarah Matthews gave testimony on the January 6th hearing and said it was expected from all the White House staff.

Earlier this year, Trump's valet, Walt Nauta, was charged in the stolen documents case. His legal team is paid for from monies collected by Trump's reelection campaign funds.
Last week, the Mar-a-Lago head of maintenance, Carlos De Oliveira is now facing a possible prison sentence for allegedly assisting Nauta, on Trump's orders, to hide documents and destroy evidence. He's scheduled to turn himself in today to be formally charged with a crime. The same as Walt, his legal fees will be paid for by Trump.

What cost is the loyalty for these two?

I give them a 98% chance they will see prison. How long? Some legal advisers estimate as much as 10 to 20 years. Walt, could get more than Carlos as he lied to investigators. Carlos, was only acting on instructions from the boss and would probably receive a lesser sentence. The question is did they cut deals with Trump not to flip and turn in information on Trump that would get them lesser sentences?
We have no way f knowing this.

What guarantee do either of these guys have that their silence will get them and their families financial protection for loyalty? There is ALWAYS the possibility that Trump could renege should he feel they didn't do enough to support him.

We've seen a handful of lawyers defending Trump decide to leave the team. Were they not paid? Trump has a history of complaining and not paying his legal counsel. The smart ones want money up front. Now it's not (so much) the money, it's career suicide to (attempt to) defend Trump without risk for the clients they've already been paid to defend. Touch subject for that matter.

Michael Cohen stated it's best for Walt to to 'flip on Trump' and take a plea deal for a lesser sentence. After Carlos appears in court today, Cohen may give the same advice.
You will know where you stand with the court and... maybe not with Trump.

My opinion based on historical events. Possibly you may have a different perspective.