An update from my side. I brought this issue up to our CPA and he is aware of the problem affecting many of his clients with no solution available.

We both agreed that a large company like Intuit not being able to fix this for so long is utterly surprising.

Essentially, by the client not being able to use Intuit Link, the accountant has to type in all the information -- which results in more administrative revenue for the firm (and Intuit's core customer.) Both the CPA and Intuit benefit at the expense of the client.