Dear Drb,
You can create a scheduled flow to add a new response and updated the existing responses automatically in each specific time.
You can add the ID column in Excel for the flow to find the rows to update the values.

Form:

You can create the flow as follows.

Use the Send an HTTP request to SharePoint action to get all the latest responses.
https://forms.office.com/formapi/api/forms('formid')/responses
For your reference: Power Automate: MS Forms responses to Sharepoint - Microsoft Community

Get each question field's value and append them to an array.
Compose: outputs('Send_an_HTTP_request_to_SharePoint')?['body']?['value']
Compose2: items('Apply_to_each')?['answers']
Compose3: json(item()['answers'])[0]['answer1']
Compose4: json(item()['answers'])[1]['answer1']
Compose5: items('Apply_to_each')?['id']
Append to array:
{
"QuestionA":"@{outputs('Compose_3')}",
"QuestionB":"@{outputs('Compose_4')}",
"ID":"@{outputs('Compose_5')}"
}

Get all rows in the Excel file and get the rows existing in the HTTP response but not in the Excel table.
@not(contains(body('Select'), item()))

Then get the number of the rows in the Excel table.
Compose6: length(outputs('List_rows_present_in_a_table_2')?['body/value'])
If the conditions that number of the items from the HTTP response is not equal to the number of the rows in the Excel table and the values of the List rows action is not empty are true, add the new rows in the Excel table.
Condition:
empty(outputs('List_rows_present_in_a_table')?['body/value']) is not equal to true and int(length(variables('Response'))) is equal to int(Outputs)
get each value of the new rows which needs to be added to the Excel table.
Compose7: items('Apply_to_each_2')?['QuestionA']
Compose8: items('Apply_to_each_2')?['QuestionB']
Compose9: items('Apply_to_each_2')?['id']
Add the new rows to the Excel table.
If the conditions are false, update each row.
Key Value: items('Apply_to_each_3')?['ID']
QuestionA: items('Apply_to_each_3')?['QuestionA']
QuestionB: items('Apply_to_each_3')?['QuestionB']
Compose9: length(outputs('List_rows_present_in_a_table_2')?['body/value'])
If the conditions that number of the items from the HTTP response is equal to the number of the rows in the Excel table and the values of the List rows action is not empty are true, update the rows in the Excel table with the items' values from the HTTP response.
Condition:
empty(outputs('List_rows_present_in_a_table')?['body/value']) is not equal to true and length(variables('Response')) is equal to Outputs
Update a row:
Key Value: items('Apply_to_each_3')?['ID']
QuestionA: items('Apply_to_each_3')?['QuestionA']
QuestionB: items('Apply_to_each_3')?['QuestionB']

Welcome to share any updates at your convenience.
Your effort and time are greatly appreciated!
Sincerely
Cliff | Microsoft Community Moderator