You've outlined the problems with 2019 TurboTax well in regards to not activating at this point in time. I realize this is anecdotal, but I still have my 2019 TurboTax installed on my PC using Win 10, and it opens and launches OK with no request to re-enter the license code. So I don't know why yours asked for it again, or were you reinstalling or tried to update the software? [EDIT: Or maybe you had a configuration change in your system as I explained in a second comment below.]
In any case, if you wish, you can fairly easily let Intuit/TurboTax know your experience and opinion at the highest level; i.e, the Office of the President of Intuit. Here's how:
You can contact the Office of the President of Intuit at the page linked below, and they claim they will report back to you within 1 business day. In the contact form there, you can enter your narrative that explains your problem and product dissatisfaction, including the bad advice you got from Customer Support to purchase a new copy of the 2019 software. I don't know how they will respond, but they need to hear from dissatisfied customers concerning their products.
https://www.intuit.com/company/contact/office-of-the-president/
