At what point did admin work start competing with building your product?

I’m an early-stage solo SaaS founder and one thing that caught me off guard wasn’t building it was everything around it.

Client emails, scheduling calls, sending invoices, following up. Individually they’re small, but together they’ve been a huge time sink.

I’m curious what non-product task ended up taking way more time than you expected while building your SaaS?

And did you find a clean solution or are you still duct-taping tools together?