As of now, it is close to reaching 100+ subs.
You can read it at https://smmry.tech/
I eventually pivoted my attention to building software again, but I write a (more niche, investor-like) newsletter for about 100 people interested in my product's progress.
The biggest tip I have is consistency. Folks like when you publish on a schedule.
You can read it here: https://rishikesh.substack.com/