Sharepoint search column and connecting more data based on selection

So context: I have a List where users request to create a new client in our database, with about 20 columns (client name, tax id, address, payment method, billing address, etc).

Now I need one to request to modify them. Been trying to set this up so that the start point is a search column from the Client name, and based on that it auto fill all the already filled out fields in the original list. However I dunno how to go about this... Is a Flow the only way possible?

My end goal is that the user in the Modifying list can pick the Name of client, pick WHAT he wants to edit, and those old fields appear. So that he can then write the new fields that should be (example, he picks Client apple, then picks Tax ID, the old one appears and a text box for changing appears as well). That may the end user can see from what to what is the requested change on that specific client.