How to read once the text is the right level, because technique decides whether it becomes a slog again.
Look up far less than you want to. A rule that works: only look up a word if it appears repeatedly, or if the sentence collapses without it. Otherwise keep going. Most words you skip you will meet again, in a context that teaches them for free.
Read for the story, not for completeness. Not understanding some of it is normal in your own language too and you never notice.
Read in longer stretches rather than in careful minutes. Momentum is doing real work - your brain gets into the language and starts predicting, which stops happening if you break every sentence.
Use an e-reader with a dictionary if that reduces the friction enough to keep you reading. A tap is much less disruptive than a phone.
Do not translate as you go. If you find yourself producing an English sentence in your head for each line, the text is too hard.
And about retention: you are not supposed to remember the vocabulary from one encounter. Reading works by exposure over volume, not by extraction. If you want words to stick, note the handful that were genuinely blocking and put those somewhere - not thirty a page.