If the last 16 months have taught us anything when it comes to Putin and Russia—it’s that complete confusion and bumblefuckery is always a much likelier explanation than an intricate, evil genius master plan worthy of a spy thriller novel.
Also don’t see why Lukashenko would go along with this plan. Plausible deniability or no, if nukes launch from Belarus and land on Ukraine, he’s going to get royally fucked up the ass by NATO.
You can make that case against Putin, who's a complete dolt, but Prigozhin has been fairly efficient with his mercenary group, considerably more efficient than Russia's official army. So why would he risk this move, not having lined up the right officials on his side to mutiny upon his advances? The entire ordeal lasting less than 6 hours is also strange. This is why I'm not going to rule out that something else could be going on.
I'm also not discounting that this was just a blunder on his part.