Tech stack recommendations for payments, subscriptions, and email automation in Next.js?

I’m working on a Next.js website and need to implement a few features:

• Credit card payments

• Subscription-based payments

• Auto email replies for user messages

I’ve tried Supabase before, but I found their auth system a bit clunky for my needs.

Recently, I came across Reflow and followed their official tutorial—it’s great, but I hardly see anyone using it.

Also, I’ve seen Clerk being recommended in a lot of forums, but I’ve heard there might be issues when migrating users away from their system later?

What’s been working well for you all? Any advice or alternative recommendations would be awesome!😊