The bank statement importation is not a real issue but you need to realize that the debits and credits are summary amounts of what could contain one to many line items. The bank statement itself does not tell us any of these details and at best gives some understandable reference number that you can match with a manually created payment or receipt with details of one or more line items such as QTY.
We use separate POS systems and only import the bank statements into Manager and assign them to summary income and expense accounts. As we deposit the cash in bank we also have those summaries but not details available. Auditors have access during audits to both systems and get guidance/answers where needed for both so they match. I am not sure what others do but I do not think there is an easy or quick fix as illustrated by @Patch’s work around, where before importing you need to put the required line items in the description (banks do not allow long description fields) and then per receipt and payment manually split them with the required line items.
I would be happy if it could recognize debit and credit column headings amounts instead of me manually putting a - sign in front and then putting them all in the one amount column,
After a bank import it is normal for all imported transactions to be in suspense. This is because more information is required such as which account in Manager.