I’m not sure If I understand the question, however your application sounds doable.
You’d need to connect the sensor to test points on Ruuvitag and code the necessary drivers.
There is an example application with NUS in SDK examples, I think the example runs on Ruuvitag as is.
Then you’d need to merge the codes. To get 75 Hz, you have to configure a small connection interval.
The transmission times might have a lot of jitter, as NRF52 can send up to 6 notifications in one connection interval.