Hi @CRam3b92 ,
You can refer to below example:

1. recurrence trigger

You can select your own time zone here.
2.Initialize variable: create a list include all the user's email addresses.
3. Get items action: to get all the items created since last Monday and please also remember to add an apply to each action in advance and its from value is the array variable we created before.

Filter query formula:
Author/EMail eq '@{item()}' and Created gt '@{addDays(addHours(utcNow(),-15),-6)} '
//for the second condition, I just use example that for each Sunday 3 pm, flow will check all of the items created from Monday to Sunday's 3 pm and if someone does not created item inside list, flow will be able to find out and send the email notification. You can change the "-15" according to your own idea.
4. Condition:
Formula: length(outputs('Get_items')?['body/value'])

5. Send an email:
TO: Item()
Hope this can help.
Best Regards,
Hen Wang