Index Sequence Row formula using data from another cell as part of the formula

Hi,

I have a worksheet with an import of sales transactions. I'm using this formula to find all transactions within the last year.

=MAX(IF('Product Import'!$E:$E>='Product Bought'!$G$2,ROW('Product Import'!$E:$E)))

I want to use the result of that which is in cell B1 as part of the formula below to auto populate a column with everything from that row upwards. It works without using cell B1 in the formula but if I use cell B1 it only returns row 1.

Works

=INDEX('Product Import'!K:K,SEQUENCE(ROWS(1:2907)),1)

Result

etc

Doesn't work

=INDEX('Product Import'!K:K,SEQUENCE(ROWS("1:"&B1)),1)

Result

Can anyone help?