He suspected British spies were behind the murder, although the actual perpetrators were a group of

…local puppets content with the whole place being a British economical colony.

Paul’s policies supporting the middle classes had been seen as threatening the Russian nobility.

Paul’s policies opposing export-oriented slave driver economy had been seen as threatening the major landowners who ran it. The rest of nobility was not necessarily united in this or any other position.

The same conflict flared later under Alexander II.

Something similar happened in USA, but the pro-protectionism industrialist faction and pro-Britain slave driver faction were geographically separated, so the industrialists could amass power and win (if at the cost of a poisonous alliance).

that the nobles were going to demand his father’s abdication (which they did indeed secure, before they stabbed, strangled and kicked the Tsar to death).

As a side note, they killed him in part because the word of this coup got out, and a mutiny opposing it was on the table, so the participants expected their extortion to be reverted with bayonets once garrison troops reach the palace. Because the common people knew which side of their bread is buttered too, and the garrison soldiers were common people.

That said, if Paul I was politically savvy and did not push away what little patriotic aristocracy he had, it’s entirely possible that the coup could be deterred, and/or this swamp would be successfully dried under his rule.

I know my answer, but I did have to consider it for a moment.