If I can offer some advice and plug my own work, I did a blog that breaks it into tiny pieces, helping put them into the Lord of the Rings context, and clarifying what you actually need to remember and what you can just let wash over you. The book is a slog for everybody the first try, and I was trying to help people through that.

https://www.quora.com/q/cowpyhwvlbspffvw?sort=top

The blog is a rough draft of what I'd hoped would some day be a completed work, so it's not everything I'd like it to be. But I do think people will find it helpful nonetheless.

Don't try to read it in book order/chronological order. Instead, start with "Of the Rings of Power and the Third Age" (which has a brilliant short retelling of LOTR), then "Akallabêth", then "Quenta Silmarillion" and only then "Ainulindalë".

They are all largely self contained, and it's much easier to go through in quasi-reverse order. Just use the Wikipedia synopsis to get up to speed on the chronologically preceding section first. (https://en.wikipedia.org/wiki/The_Silmarillion#Synopsis)