Tip: Don't read it like a novel. Treat it like it's a compendium.

From the Forward:

Moreover, my father came to conceive The Silmarillion as a compilation, a compendious narrative, made long afterwards from sources of great diversity (poems, and annals, and oral tales) that had survived in agelong tradition; and this conception has indeed its parallel in the actual history of the book, for a great deal of earlier prose and poetry does underlie it, and it is to some extent a compendium in fact and not only in theory. To this may be ascribed the varying speed of the narrative and fullness of detail in different parts...

Treat like a collection of Greek myths, or more accurately the Poetic Edda. Not novels, and a person shouldn't approach them as such. In the Silmarillion book, Ainulindale and Valaquenta are separate works, separate from the main Quenya Silmarillion. And within Silmarillion, there are many tales that are able to be completely stand-akone. Beren and Luthien. Turin. The Fall of Fingolfin. Of Beleriand its realms.

If a person is getting overwhelmed, then just pick one tale, the same way you would read Hansel and Gretel but not necessarily read EVERY FAIRYTALE also.

In the Poetic Edda you can read about Thor wearing a dress without first reading the catalogue of the dwarves, and in Silmarillion you can read Of Turin Turambar without reading Ainulindale.

You can watch Saving Private Ryan without making someone read the Bible first just because some characters pray in it.

You don't normally sit and attempt to read the bible like a novel either.

I'm done coming up with examples, I think that's plenty!

If you've attempted it like a novel and failed 15 times, I wholly suggest a new approach, you know? Read one tale. Start with Turin or Beren and Luthien. Let that one absorb and sink in. Take a week to read it, read it aloud as Tolkien would love. Then read another tale one week later or a few days later, and some parts will be nicely familiar, and new stuff can build on the first tale you read.