Kylep,
Quotes are special characters so they must be escaped to be included as part of the query text. Please modify your Search filter text as follows
received:\"last week\"
I have found that for text lookups, the match is literal from the start of the text. It is not like in outlook that you can type a string and it will find all text that includes the string. For example in outlook client, if you type subject:val, it will find messages with value, valid, evaluated, oval in the subject. If you use the same criteria in flow, it will only match the word val.
Pd, and drop the parenthesis
Cheers
Fernando