Let's get to social democracy first and then we can talk about communism
But that's the thing, social democracy is just a tool used by capitalists as an attempt to stop-gap the inevitable decay of capitalism. If we can just "do social democracy then talk about communism" why didn't the New Deal lead to communism rather than end up at the neoliberalism that is responsible for this current state of hellworld? Why didn't all the "Nordic model" countries achieve communism after supposedly being the paragons of social democracy, countries who are now sliding further and further to the right and even into fascism? Capitalism by its very nature is something that cannot continue indefinitely, its internal contradictions (from the inherent insolubility of class antagonism to the requirement of infinite growth on a finite planet) are such that it will always tend towards its own destruction. Look into "The Tendency for the Rate of Profit to Fall" to understand that social democracy cannot prevent the declining rate of profit and in some ways even exacerbates it.
There is also the fact that social democracy still necessitates imperialism: the exploitation of the people who don't live in the imperial core (so called 3rd-world countries) to support those who do live in the imperial core. It's easy for the beneficiaries of social democracy to say "let's not be hasty, we don't want to disrupt things too much" while the great masses of people in other parts of the world are suffering and dying in poverty to subsidize the easier lifestyle of the social democrat, sitting comfortably with their citizenship that provides them the "social safety net" that is denied to the children toiling in mines, or drowning in the oceans they attempt to cross to "illegally" gain access to a piece of that privilege their exploiters enjoy.
Also, this debate has been had so many times before (look up Lenin's beef with Kautsky, or better yet read Luxemburg's Reform or Revolution), and those who fall into the trap of revisionism have always eventually been shown to be on the wrong side of history. And by revisionism, I mean the opting for capitalist reform despite the scientific theoretical framework of historical materialism showing us, and accurately predicting that capitalist reform will forever remain inadequate to solving those internal contradictions, only delaying them at best.
From what I can see, you are someone who is genuine with their "heart in the right place," but what you need to look at is how these questions you're posing have all been answered already, but because those answers are a direct existential threat to those with all the power, those whose interests lie in maintaining the status quo at all costs, those answers have been demonized and ridiculed and suppressed, and worst of all, been said to be impossible, unachievable ideals. They are not only achievable, they are immediately necessary if we hope to stand any chance of mitigating and surviving the climate change (that capitalism wrought) before the earth is too scorched to even support our species, let alone civilization. Social democracy would have us set that little issue "on the back burner."
You're very welcome, it's nice to read an appreciative response! And yes, there is a ton to digest especially for anyone that hasn't really been exposed to these ideas before. Marxist theory (which for the record extends far beyond just Marx - just as modern biology extends far beyond Darwin) is something that I'm still in the process of digesting myself and I expect I always will be. But it also starts helping a person to make sense of the state of the world very quickly, even if they've just started the meal. @Cowbee@lemmy.ml has an excellent reading list if and when it's something you want to really delve into. Also, the podcast RevLeftRadio has some really good episodes just laying a lot of the basics out on the table.