I am also still learning, but I can share this. I am assuming that you are referring to ‘social democracy’ and similar reformist movements. The SPD (as in Germany and its many international affiliates) and the DSA (in America, though many will argue that there is a meaningful Communist contingent within the party, despite its leadership). Communism as an ideology is defaultly more democratic than the current system of liberal capitalism, which these movements have been trying to reform. Hopefully I have not misconstrued your question.

A primary concern with this basic choice between liberal reforms and ‘actual Communism’ is that it is vulnerable to ‘recuperation’ by the current (imperial) stage of capitalism’s development.

Here’s how it would work: we say that we want reforms to gradually transform society into something that works for all people, including the working class, not just the economic elite. As an example, I’m going to pick on a common slogan in the West that goes, “Spend money on people (here in this nation), not war.” Remember that a change like this requires a mass movement, we can’t just agree in a few small rooms across the country; this has to be a movement that will involve all of working people across society pushing together to change what is unjust.

Remember that the exploitation that funds capitalism comes from home and abroad: not just war, not just militarized seizure of oil assets and political extortion, but also privatization of critical industries, “trade” with a less industrial developed partner that leads to the enrichment of the richer economy and the impoverishment of the poorer, and any example that lengthens the reach of the powerful nation over the weaker.

So, here is the capitalist solution to the reformist “problem”: stop being so selfish and share more of the profits not just with the 1%, but with the 5% – a larger population of people in the imperial core. Satisfy them until they don’t feel the economic pinch anymore and stop wanting to organize. Give them a show trial. Give them a hospital. Whatever it takes to “reform” the people’s attitude until they no longer want to change the system. All the meanwhile, continue to exploit people outside of your borders, perhaps in ways that include war.

edit: At some point, some people in this movement will become satisfied by the gains. They will see the ‘fascism at home’ end, and they will not see the ‘imperialism abroad’, so they will give up the struggle. We need them to keep struggling until the exploitation ends. In this way, reformism has no solutions, where other the other ideology has invested a great deal of human effort looking for solutions.

We should push harder for a form of society where luckier people don’t have so much power over those who are less fortunate. Directionally, that is Communism, not a reform of liberalism.

My criticism is fairly limited to this one example that I gave, but I hope that it is still helpful. Interested in feedback on my framing from those who are more read. :)