It's not a dumb question.
That said, let me be blunt.
Mixing stimulants and opioids like that, even with something as "mild" as vyvanse, is still a form of speedballing. And yes, the effects can be unpredictable and dangerous, but not in a peaceful way. The stimulant speeds your heart up. The opioid slows your respiration down. Your brain gets yanked in opposite directions, and if you don't pass out from one, you might seize from the other. And that's before you add a benzo or a beta blocker to the mix.
Most overdoses from that kind of cocktail don't result in death. They result in organ damage, brain injury, vomiting while unconscious, or waking up hours later in a hospital bed surrounded by people you didn't want to see. Or worse: waking up alone, with half your memory gone and a body that doesn't work the same anymore.
Vyvanse, for what it's worth, is a prodrug. That means it has to metabolise in your liver first before it kicks in. So by the time it's active, you've already potentially slowed your system way down with the other drugs. You could be sedated or disoriented before the stimulant even peaks, which adds a whole layer of confusion and chaos to your body's response.
If you're trying to build something reliable and peaceful? This isn't it. And I'm not saying that to scare you—just to be honest. A lot of people try these kinds of combos thinking it'll just "stop" things. But more often, it just makes the suffering worse.
All the info's out there. Take your time. Read
this.