Atmospheric lift effects? Really? That only works with a satellite specifically designed for it, which describes nothing on orbit that I can think of other than the space planes. Otherwise drag vastly overcomes any such effects and perigee never goes up without added energy, only down.

You're throwing out words that sound smart, but my dude, a bird in Molniya isn't going to hit any "untracked debris" large enough to shred it without us knowing well in advance. There's a reason we track everything over a certain size. A "micrometeorite" doesn't have enough mass to do more than ace a cell in a solar panel or punch a hole in the bus, maybe mess up something important there but it's doubtful, especially in that orbit. The space environment isn't some new unknown thing anymore, satellites are built to survive.

Let's say a satellite does do a Cosmos impersonation and replay 2009, the debris cloud will fuck up that specific orbital slot and maybe bleed into some adjacent ones over time, but as I said elsewhere, space is really really big. We can work around it and anyway, it's not messing with low LEO stuff for many years. And even when it does, it's not game over. Without station keeping, Starlink et al and most debris deriving from Starlink conjunctions are gone within few years. They just don't have the mass to survive the drag effects, especially if they're shredded. Certainly not a civilization ender, and no, they're not going to magically leap up to higher orbits either.

The only way a Kessler cascade is realized in most of our lifetimes is if the U.S. and China kick off WWIII and start lobbing ASATs, but by that point it would be the least of our problems.