First, don't apologize. Believe it or not, those are some of my favorite problems to solve.
An intermittent problem with no codes is one of the hardest things in our industry. The fact that three shops haven't found it doesn't necessarily mean they're bad shops—it means the vehicle hasn't failed while they were testing it.
If it were in my shop, I wouldn't start by replacing another part. I'd start by asking one question:
"What disappeared when it lost power?"
Did it lose fuel?
Did it lose spark?
Did it lose throttle?
Or did the computers lose power?
Those are four completely different problems.
I'd also want to know exactly what "loses power" means. Does the engine stumble like someone turned the key off for a few seconds? Does the RPM drop? Does the transmission downshift? Does the radio stay on? Those little details point us in very different directions.
One thing I've learned over the years is this: intermittent problems usually leave evidence—you just have to catch them in the act. That's why I road test with a scan tool recording live data instead of just checking for codes afterward. Many failures never set a code, but they will leave clues in the data stream.
I've found problems like this that turned out to be a failing crank sensor, a loose ground, a bad ignition switch, an intermittent fuel pump, a corroded connector, or even a broken wire hidden inside the insulation.
My advice? Don't let anyone keep throwing parts at it. Find a shop that's willing to diagnose the failure instead of guessing at it.
That's where I'd start. That's how you find the one thing everyone else has been missing.