I need to build a clent questionnaire I can host on my site

I've got a questionnaire I want clients to fill out in order to build a report for them. I will take the written information from the answers, rather than analysing it via a database. A Phase 2 might be for the answers to autopopulate a document I will use to build the report itself.
The answers might be paragraphs, links or attachments. It might be that they want to circulate the questionnaire around the company to get all the info, and it would be useful to be able to tag people.
There will be approximately 10 clients completing them each month.

A google doc does the job but doesn't look very professional.
I'm looking for a third party tool that would a) collect the info, b) allow people to be tagged to complete elements and c) looks good.
It's more than Typeform I'm looking for, because I want them to be able to refer back to previous questions easily as you would in a doc, rather than being taken through a linear survey.
Ultimately I want to be able to charge a decent amount for the report, so want the customer experience to be as smooth and professional as possible.
I'd consider a third party tool such as Air Table, Notion or Coda. And I'm also open to building something bespoke.

I'd be interested in proposals that include a recommendation as to what should be built, on what platform, and a cost estimate.