The USSR's "peaceful coexistence" during the Cold War was simply them trying to avoid WW3 with the US, especially after how much WW2 devastated Soviet society and how far it set them back in their economic goals. It wasn't an incorrect position to take given the US still had an immense amount of production capital before the neoliberal turn and, if the USSR were to hypothetically enter a hot war with America, they would likely lose it solely because the US would be able to outproduce them.
And even before WW2, the USSR was already doing peaceful coexistence with capital from their policy of 'Socialism in one country', because they realized after the failure of socialist uprisings in other European countries in the 1920's, they were alone in the world and surrounded by the enemy. Trying to be more 'proactive', which is what the Trotskyists wanted, would have been tantamount to self-destruction.
The PRC and the rest of the Marxist-Leninist states today continue the same doctrine, because it works for them today as it did for the Soviets back then.
It should also be noted that some of the interventions that the USSR did undertake ended up eliciting resentment from the local populations towards Soviet Communism. The Soviet-Afghan War is a prime example, but it can also be seen in their suppression of protests and politicians that didn't toe Moscow's line closely enough in Eastern European SSRs (which, while understandable, did create a big impression from the people that the USSR was an occupier getting in the way of self-determination).
Mao's criticism of the USSR conducting 'social imperialism' during the Cold War was an apt one when, in the cases I noted beforehand, it was very much the Soviets trying to impose their will and ideological line on foreign peoples, instead of allowing left-wing movements to grow and develop organically. I personally believe the Belt and Road Initiative is China's way of allowing the latter idea to occur, but it's not without its faults, and it remains to be seen if it will succeed.
Let's not forget the PRC themselves made several mistakes in their attempts to export Socialism abroad too; backing the genocidal Khmer Rouge, sending the PLA into Vietnam to "teach them a lesson" for removing the Khmer Rouge, and the Sino-Soviet Split itself causing a massive rift in the International left that greatly stunted the ability to organize against global capital.
Again, I'm not trying to argue that it's wrong to try and instigate revolution abroad and back anti-colonial movements (DPRK indirectly supplying weapons to Palestinians is based), but that there is a lot more historical nuance behind the modern geopolitical strategies of AES.
If I may ask, what do you believe the USSR should have been more proactive in in regard to their interventions abroad?
Look, Rom, Rom...I know you're a sophisticated guy. The world is a mess. The world is as sick as it gets. What you think this gonna cause a little more sickness? The world is a sick place. All of this has happened: we went into lockdown- we shouldn't have gone into lockdown.