Same orbit or not doesn't matter, what matters is distance, and things in different low orbits (most satellites) are all pretty close to Earth and hence each other when orbits line up. They definitely can't just move satellites away, as satellites have very limited manoeuvring capabilities, and changing orbit takes a lot.

The EMP of Starfish Prime [1], the detonation of a nuclear bomb at 400km altitude (the altitude of the ISS), knocked out streetlights over 1400km away in Hawaii. That means it could have damaged satellites up to at least 1800km altitude (but this was in 1962), which is almost all of the low Earth orbit altitude range. With enough nukes you could probably wipe out Starlink's satellites, but with the way they're spread out, I think you'd wipe out most other satellites too.

[1] https://en.wikipedia.org/wiki/Starfish_Prime