Growth for niche developer newsletter?

Hey pals, I have recently started Dev to Agency - which is a newsletter and blog about my experiences and advice going from a full-stack developer (8 years ago) to starting and running a custom software agency that made 7 figures per year (and was acquired in 2020).

It's pretty niche as its aimed at developers that want to start an agency (almost the opposite of the IH crowd!), but I thought it could be good to get your thoughts on growth, and where I can find an audience that may be interested.

I am pretty inexperienced with this and mainly just focusing on writing the content, but I realise I need to get out there and promote it otherwise I am just sending it into a black hole :)

Any advice is much appreciated - thanks all!