FYI, Project and Visio in particular aren't part of the subscription model. They aren't actually available as part of any of the consumer Office subscriptions, so they're offered as one-time purchases of the Project/Visio 2019 software, same as the old HUP model.
That said, they're also not available by default. The FAQ[1] page mentions your HUP/IT Admin needs to explicitly set up your HUP to enable these product discounts.
As a former IT Exec these were the two products that caused me the most significant end-user software budget headaches (in a 1K+ seat banking org)!! Clients who needed the odd flowchart or gantt chart HAD TO HAVE project or visio or else IT was denying them the ability to do their job!! It took quite some effort to get the culture shifted towards open-source alternatives that were good-enough and didn't line Microsoft's already golden pockets.
That said, they're also not available by default. The FAQ[1] page mentions your HUP/IT Admin needs to explicitly set up your HUP to enable these product discounts.
[1] https://www.microsoft.com/en-us/home-use-program/frequently-...