hi there,
You can always donwnload your licensed copy of Visio 2019 from your MS account. I've done this at least 10 times. That's the big deal with 2019 vs 2016. For 2016, you needed your key code, for 2019, you always have it because its part of your ms account. There are other bugs, of course, but I'm pretty confident about this one.
https://account.microsoft.com/account

You can also repair. Goto applications and features > Microsoft Visio > Modify > Repair (try local and then online).

best!