Im not very well educated in Christianity, but as far as i know Jesus was aligned with communist ideals, he was extremely egalitarian

There is not much sense in trying to argue this talking point, Jesus was progressive for his time but framing him as aligned with communist ideals is a big stretch and frankly disrespectful to communists. I recommend you reading Engels' Socialism, utopian or scientific, you'll see that Jesus falls on the utopian camp with nothing to offer other than idealism.

Do you think we should think of the catholic church as a possible ally or would that be counterproductive?

The catholic church will never ally with any communist movement, the entire institution is practically merged with European finance capital, we could pragmatically, and tbh opportunistically, some of their rhetoric but other than that meh.

Do you think anti-religion is fundamental to Marxism?

Religion is incompatible with materialism, still no need to be an asshole towards religious people.

Do you think the anti-religious stance of the Soviets was a mistake?

China figured out the correct policy later on. However Lenin did not held this anti-religious stance, it was mostly a failure by the leadership in educating the party.

https://redsails.org/on-the-question-of-religion/

https://redsails.org/the-attitude-of-the-workers-party-to-religion/