Hey there, Alex. I see how precious your time is. Currently, the feature to link expense receipts directly to invoices is unavailable in QuickBooks Solopreneur.
In the meantime, you can continue manually entering the information and amounts in the invoice and add the receipts as Attachments to link it.

You might want to learn how to designate bank transactions to the correct accounts. Check out this article: Categorize bank transactions in QuickBooks Solopreneur.
For more queries about linking expense receipts to your invoices, click the Reply button below. We'll ensure to assist you. Have a good one.