There will always be a limiting factor.
For games, usually cpu or gpu.
In your case, a 2070 will always outperform a 2060
In fast action games, the difference will be apparent, regardless of the cpu(almost)
In cpu centric games there may be no difference.
The t suffix processors are made to be energy efficient and will not perform as well as the normal parts.
I imagine that you might now own a 7700t and some sort of a graphics card, looking to upgrade graphics.
Try this test:
Run YOUR games, but lower your resolution and eye candy.
If your FPS increases, it indicates that your cpu is strong enough to drive a better graphics configuration.
If your FPS stays the same, you are likely more cpu limited.