USSS won’t just let him get on a plane and fly off to Russia. His security is their top priority, so allowing him to secrete himself somewhere without first verifying his itinerary and securing both the mode of transportation and the destination, would be unthinkable. That means they are reporting all of his movements to local law enforcement. Can’t exactly flee the country in secret when every cop in the state will know his exact position and have eyes on him at all times. If the courts think he is a flight risk, someone involved in the process will know what he’s trying to do and prevent him from going anywhere where it will be hard to get him back again.
The minimum sentence is a hefty fine, but the judge in that very trial already determined that fines do not discourage Trump’s behavior, given the contempt punishment that he ignored, so I don’t think it’s going to be a slap on the wrist for him unless the judge truly is a hypocrite or a coward.
That being said, even if he gets prison for each of his felony counts, he can serve them all concurrently, a maximum of 3 years per count. So he could theoretically be out of prison right before the next election cycle with a year left to campaign for 2028, that is assuming he truly is sentenced immediately after the election in November and it’s not just pushed back indefinitely due to recount horseshit or Trump crazies doing another insurrection.
But there are other trials that are far more likely to result in additional prison time, the most important two being the classified documents case and the Jan 6th case. I have faith that the justice system will eventually follow through with punishing Trump, but the system is set up to slow-walk the rich and powerful to accountability.