You’d need to use an external system like Make.com to create that entry using Webflow’s API. That part is relatively easy… Logic isn’t quite there yet for the features you need, so you use a different automation service.
However you’ll probably also want to consider the reality that experts may need to update their listings and that means a memberships solution.
Webflow’s User Accounts feature can be used with a bit of custom coding for a simple scenario.
MemberStack offers more login options ( like using Google auth ), better docs and examples for user dashboards, at an added monthly cost.
Wized gives you a richer programming experience and if you’re thinking towards a more complex dashboard experience, I’d recommed that direction.
What I’ve outlined will get you all of the basics you’ve asked for.
If that’s all you need, you’re good to go
But… there’s a lot more you could do with this.
For example if you wanted those experts to login and edit their own entries I have a screencast that walks through how to do that by taking advantage of Memberstack:
(this is a Memberstack v1 example, using their latest & greatest v2 is an easy transition)
If you’d like to extend what you’re originally thinking, detail that here and I can give you more guidance, and most likely the right tutorials and examples for success.