Hi @flowForm ,
working with DateTime in power automate is a bit tricky. but hey Our community got your back.
I have just created small sample flow and code Take a look.
after `List rows present a table` Action

add `Get past time` action then Interval 7 then `Time unit` drop down choose Day as below

Next Add Filter Array Action :-
for `From` input add Excel value.
inside `Choose a value` use `Completion time` column
in condition dropdown choose `is greater than or equal to`
last `choose a value` use past time coming from `Get past time`

then initialize array variable give it a name

add Apply to each action as input select Body of the above Filter action.
next add Append to array variable action, choose initialized variable name from drop down
in value give Excel list item.
come out of apply to each.

below to that add Create HTML table action.
for that input select initialized variable name.

next step send an email action and insert above `Create HTML table output then finally test.

see below results.
Excel data :-

Flow Ran Successfully :-

Expected output in the email :-

Let me know How it goes.
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