sharepoint online: how to create a dynamic form

I need to create a form that collects data, optionally send an email to someone based on the content of that data, and put the data in a list.

My thought was MS Forms -> Power Automate Flow -> Sharepoint Online

Unfortunately, some of the questions that will be asked will depend on the data found in a list of shared points. (For example, we want a drop-down menu of & # 39; tags & # 39; … but we need people to be able to add their own & # 39; tag & # 39; through a text field).

How can I & # 39; feed & # 39; Custom questions in MS forms dynamically? Should I be looking for a different product?

If MS Forms cannot do this, are there & # 39; forms & # 39; of sharepoint (which allow fully dynamic content) in the o365 environment?

Thank you.