One of the most remarkable aspects of physics is that Newtonian gravity calculations are quite spot on for all the parts of black holes layfolk consider important.

1. Both predict the same critical radius, now called the Schwarzschild radius.

2. Both predict a central singularity with formally infinite density in idealised collapse.

3. Both predict exactly the same finite time to fall into the singularity under equivalent idealised conditions.

4. Both give the same equation for radial free fall, using different definitions of time.

What GR added was meaning to these things (and of course precise calculations outside of very idealised scenarios and symmetric conditions).