Orbits are elipses, which are loops. So after the explosion gives an object more energy it's in a new orbit right? That orbit has LOOP. Which means it has to come back to a similar point it's at now. Therefore if an object passes through low orbit, no one explosion can make it be in a high orbit. At best it'll be an ellipse with a point in high orbit and a point in low orbit.

Any amount in low orbit means a decaying orbit due to drag with eventual falling out of the sky.

If you get to the high orbit point and you get a SECOND explosion that's perfectly timed you could theoretically enter a new high orbit that's stable over the long term and contribute to Kessler syndrome.

Which it absolutely will, at least in the sense no part of the ellipse is lower.

Happens all the time with meteors. There's a lot of atmoshpere and only so many Starlink satellites; far too few satellites to meaningfully affect anything.

Yea but you still have to get the GPS satellites up there safely. I see though that it might actually not be that big of an issue of GPS.

Yes, but a screen of tiny reflective particles spread through orbit between the Earth and the GPS satellites might cause communication problems.