Browser extension? Try these: http://www.paper2audio.com/ https://freevoicereader.com/ https://chromewebstore.google.com/detail/sza-text-to-speech/... https://chromewebstore.google.com/detail/flow-tts/hknidankih...

I found all these on this subreddit: https://www.reddit.com/r/TextToSpeech/

I've also see comments like "Microsoft Edge's read-aloud feature is amazing for TTS" but I haven't tried it myself.

Personally I use Kokoro with a python front-end on my Macbook, I linked to it in this comment: https://news.ycombinator.com/item?id=49818923 it outputs MP3, so I just copy those to my phone and listen as audiobooks.