one thing that keeps getting skipped here... before you build anything, test if people actually want it. you dont need an smm panel or a hosting setup to validate. just dm or post in a few groups offering the thing and see if anyone bites. saved me from wasting months on stuff i thought was a great idea but nobody cared about.
also recurring beats one-time every time for cashflow. a $30/mo thing thats boring but sticky will outpace some flashy product you have to resell every day. that local automation angle works because of that, not because the work is fun.
if you wanna keep it hobby-ish, pick the niche you already lurk in for free. you already know the language, the complaints, what they overpay for. for you with the hosting background, managed wp or done-for-you setup in one narrow vertical seems like the obvious low hanging fruit honestly. start small, one client, see if you even enjoy the support side before scaling anything.