I've been meaning to follow the "talk to your customers" advice for so long and have finally been pushed to do it by joining the Sales For Founders course (https://salesforfounders.com/)
I sent out ~100 emails to existing customers and ended up having a couple of email chats, one real life conversation (in London) and 6 calls.
In all honesty, I learned less than I was hoping. I struggled to get into the details of what the customer's goals were, what they cared about, their pain points etc.
I did, however learn some things. I learned that Page Flows was more valuable than I initially assumed. Churn is high at the moment, so I assumed that meant no one found Page Flows valuable, but that's just not the case. I do need to figure out the churn problem though, and continuing to talk with customers (and ex-customers) will be part of that.