Substack vs. ConvertKit—Is there a way to get the best of both?

I run a large free newsletter on ConvertKit and am thinking about moving to Substack to start monetizing.

The big issue is that Substack doesn’t integrate with anything, which makes things complicated.

I’d still need ConvertKit for things like automations (e.g., my welcome flow), most of my subscribers come from a free quiz where the results are automated through ConvertKit, etc.

My other concern is Substack's lack of tools (like A/B testing, pruning cold subscribers, automations) and it seems like the analytics aren't great.

I was thinking I could cobble together the two solutions -- e.g., keep convertkit for welcome flow / quiz results -- and have my assistant add my new subscribers to Substack each week, and just give up some things like A/B testing in order to get the network benefits / monetization of Substack.

Is there an all-in-one platform that can handle monetization, automations, integrations, and analytics (and network benefits)?

Has anyone else cobbled together Substack + Convertkit and how has it worked for you? Curious to hear from anyone who’s navigated this!