I am currently using this website to get the 10 highest-rated "Ask HN" weekly. The website doesn't provide a newsletter subscription. But, there is an RSS feed that you can subscribe.

https://www.daemonology.net/hn-weekly-ask/

As a side note, I just want to say thank you to Colin Percival (@cperciva) for creating this. I am not sure you will probably read this :)