- Every country has different customs regulations, so paperwork is not really that reusable across ports.
- Customs is a huge source of fraud. In poorly managed countries it is one of the prime vectors for bribery and corruption. So destination ports have to verify everything even if they do receive the paperwork, because there’s no trust.
Generally speaking if you want to cut customs red tape your options are some kind of free trade deal (which is not necessarily popular and never covers all types of goods), or banding together with a bunch of different countries to submit to one supranational entity like the EU. In fact we have a live example of how complicated customs arrangements can be; look at how trade from UK to EU has been disrupted by Brexit and the introduction of customs.
The government doesn't seem to consider the huge hidden cost to the businesses in the country this represents, and the businesses haven't been stellar at highlighting it, which I guess is because they mostly just push that cost onto the consumers.
It's also not just customs, there are a ton of ancillary processes related to berthing - things like harbor fees, environmental documentation etc.
I know of at least one case where, as recently as ~2015, a shipping company had to keep around old machines with IE8 because that was the only way to interact with authorities at a given port.
If your paperwork is mostly driven by other actors tech probably won’t help all that much. Tech has not made significant inroads in disrupting American health insurance, for example.