Energy conservation when adding braking resistor to H bridge?
This is for inductor stored energy
So, if you discharge a charged inductor onto a 1 Ω resistor, the instantaneous current will be the same as you connecting the inductor to a 1000 Ω resistor but, the whole show will be over much more quickly. In other words, with a 1 Ω resistor, it might take 1 second for the current to reach a level of one-tenth whereas for the 1000 Ω resistor it will take much, much less time and...
...the total energy taken by both resistors over a long time period will be the same. They will both get warmer by the same amount (assuming perfect heat insulation).
The energy that either resistor receives is \$\dfrac{1}{2}\cdot LI^2\$ where \$I\$ is the instantaneous current at the point when the resistor is connected to the inductor and, that current is defined only by the inductor (as we know).
For energy due to mechanical momentum
This is different and there is no correlation as implied here: -

The braking power is still the same, -EI, since the current has not
yet changed thanks to the inductor.

So, don't mix up the two.