It’s hard to tell to tell what exactly your video is showing. If a user needs to make several dropdown choices for each of the 30 items they are adding to a receipt, then it is going to take a bit of time to enter them all. Each of those pieces of info need to entered independently no matter what format you use.
One of the appeals of mobile-based apps is that they break larger processes into smaller pieces to provide more focus to each piece and less chance user data entry error. Plus each piece is saved so that if anything goes wrong part way through, the user can re-open and restart where they left off with minimal need to re-enter data.
But, if your complaint is concerning the number of times users have to tap Save and then tap Add again. there are a couple of other option to help with this.
One is what you have mentioned - using Auto Save and Auto Open. This, in my opinion, is the best. If it is setup right, the user is guided through the entry of the items while still being focused on one item at a time and saves occur at the end of each item entered.
The other is build an Editable Table view such that all rows for the items to be entered are shown together in the view and the user walks through the columns for each row setting the values. Similar to editing a spreadsheet. The idea would be to ask up front how many item entries are needed and then the app transitions to the editable table view with that number of rows displayed for the user to select the values. All values are selected, e.g. uses goes through all 30 rows and selects the necessary 3 or 4 values needed for each row, and then once done, Save is tapped and all edited rows are updated.
The down-side is that if anything happens while the user is in the middle of entering data into the editable table, they could lose all their entries and have to start over.
The only other possibility is if data can be pre-staged somehow. For example, you haven’t mentioned how the user knows about the 30 items that need to be entered on a receipt. If the user has a document they are referring to, there are likely capabilities that would allow you to use OCR technology to scan the document, extract the data and automatically add those details into the app.