You can use the Import Template of Quote Product for new Product Line Items.
Go to Data Management -> choose Templates for Data Imports.
But, since it is a Product Line Item, you need to have the Quote header first then you use the Quote ID as the reference to link the item lines to the Quote.
Using this Data Import will help you to do bulk import using Excel with the format same as the data required by CRM in the Form.
Then as usual, do your import task, import to the Quote Product entity and mapping it (if you didn’t change any field name, it should be fine if you using import template, no need to change the mapping).
Hope this helps!