I'm guessing you have 3 different flows, 1 for each of the forms?
For each of the flows you should add the steps that will List Rows in a table, filter the table by the person's name (Would be better if you had a unique identifier like employeeID or their O365 account principle name), then a condition to check if the name exists.
If the name does not exist, then add a new row with the form response.
If the name does exist, then get that row ID and update that row with the form response.
Could you add a unique identifier like employeeID or use their O365 account information?