Why is LE a quantifiable threat to Paradox space and Bec Noir wasn't? Both are incredibly powerful entities born Sburb sessions that are likened to deceases that destroy universes.

First of all, this was a quote by Doc Scratch trying to magnify the threat of Bec Noir to convince Rose to detonate the Tumor in the Furthest Ring, so that’s a thing to have in mind. Beyond that, however, Lord English is the Lord of Time, his existence is basically a Time Loop that Paradox Space needs to follow, from his Birth to his Destruction, all the events leading from the beginning to the end are immutable and planned. Lord English infiltrates and destroys Universes until the Great Undoing, when his reign comes to an end. His influence has a finite reach, by the mere nature of it. Bec Noir, however, is a Rogue Agent with First Guardian Powers, with a reach not limited to the Alpha Timeline, and who likes fucking shit up as much if not more than Lord English. He’s not as powerful as the Big Man himself- But without PM going after him for three solid years, he would’ve been a way, way more unpredictable force. Hell, even AFTER he loses his First Guardian powers, he takes over the Felt and heads to Earth-C where the Kids are, the guy is just relentless in his ambitions to do stuff. Lord English is trapped in his own cycle of destruction, but Bec Noir can do as he pleases.