correct IAP-type for daily purchases

There are two ways:

1) a consumable 'credit' that can be exchanged for any daily issue. You will need to record (in the user's iCloud key-value file for example) the daily issues that have been purchased by that user.

2) a subscription - either non-renewable or autorenewable. The user is entitled to view/download any daily issue that comes out during the time period that their subscription was in effect. You can use the receipt to determine those time periods.

Couldn't that cause problems with the review?

If you define an IAP as Consumable, but it has a different meaning.

Unfortunately, subscriptions cannot be purchased for a past period.

Therefore you could not buy old issues this way.

I'm afraid the second idea wouldn't work.

Anything can cause a problem with App Review. This use of a consumable IAP to purchase 'credits' is consistent with the guidelines, IMHO - but, again, anything can cause problems with App Review. The credits are consumable hence a consumable IAP is appropriate. What they turn into is not consumable - therefore you will need to create your own restore function using something like the user's iCloud key-value file.

> Unfortunately, subscriptions cannot be purchased for a past period.

Yes, past issues (this is your first mention of this product line) would need the Consumable IAP credit system. Current/future issues would work under a subscription system.