How do you make a paid tier feel different, not just gated?

Ran into this problem last week: my free plan and paid plan were doing the same thing, just with a lower number on one side. Free users got a report and a tip. Paid users got... the same report and tip, regenerated with a slightly longer prompt. Nobody's upgrading for that, and I don't blame them.

What actually fixed it wasn't adding more features; it was making the paid tier answer a different question entirely. Free tells you what happened. Paid finds out why it keeps happening and gives you a week-long plan to fix the actual root cause, not just today's symptom. Same data, completely different job.

The part I'm still not sure I got right: how far do you take that gap before free starts to feel deliberately crippled instead of just simpler? I don't want it to feel punishing to not pay; I want paid to feel like a genuinely different product built for people who are serious about the outcome, not just "free but slower."

If you've shipped a free/paid split, where's the line between "simpler" and "deliberately withheld"?