Yes I absolutely agree. When I was first starting I did not know Diogenes Laertius was available.
As I think about it now I do think that - ironically - the history part written by DL is the part I would focus on. When you get to the actual letters and the list of doctrines, you're again thrown into the context that Epicurus was writing to people who had access to his context and wider teachings, and these summaries can also seem overwhelming if you read them out of context.
Because DL is explaining from a generalist perspective, his own commentary part is easier to understand (though even that runs into issues such as Nikolsky explains in his "Epicurus on Pleasure" article.) As Nikolsky explains DL was often following a formula and trying to cover much the same group of topics for everyone he was writing about. Therefore the patterns in his presentation are helpful to know about - and if you don't know why he considers something to be important, it's easy to be confused.
One example is how he at the beginning of the book divides the schools by geographic regions rather than in the ways we're familiar with, so that even what appears to be straightforward can be confusing, such as labelling Epicurus part of the "Italian" school (I bet our friend Elli from Greece probably doesn't care for that
)
Diogenes divides his subjects into two "schools" which he describes as the Ionian/Ionic and the Italian/Italic; the division is somewhat dubious and appears to be drawn from the lost doxography of Sotion. The biographies of the "Ionian school" begin with Anaximander and end with Clitomachus, Theophrastus and Chrysippus; the "Italian" begins with Pythagoras and ends with Epicurus. The Socratic school, with its various branches, is classed with the Ionic, while the Eleatics and Pyrrhonists are treated under the Italic.
BUT ALSO FROM THE SAME ARTICLE:
He also frequently focuses on trivial or insignificant details of his subjects' lives while ignoring important details of their philosophical teachings and he sometimes fails to distinguish between earlier and later teachings of specific philosophical schools. However, unlike many other ancient secondary sources, Diogenes Laërtius generally reports philosophical teachings without attempting to reinterpret or expand on them, which means his accounts are often closer to the primary sources.
(And of course that is open to dispute as to what is trivial vs what is important, and it presumes that we are in a position to judge his accuracy better than he was, which is very debatable given that he presumably had direct access to the materials and we don't)