I'm not likely to get anywhere on this forum but will try once more before walking away and leaving you to it.

This is supposed to be adaptive cycling. I've put together a couple bikes for cyclists with one hand/one arm. Think about that one a minute. Just not good idea to put much weight on the one good hand. It's going to cause control problems. Excess weight on one side only is going to cause stress and then injury. And these are people who do not have an extra hand to spare. So they ride light.

A death grip on the handlebar is never a good idea.

I routinely see brakeless fixie riders doing 20mph in heavy traffic while texting. One hand to hold phone, one hand to type. I can't do it and would not if I could. But it can be done. I see them stopping quickly and stopping to a track stand while they type away. It's stupid and it's scary - it is possible.

What I have done is snap a stem clean in two and not fall. Downhill with weight on bars. And then proceed to ride home twenty miles. One hand with grip on steerer, the other hand holding the now loose handlebar that still has the brake connected. Don't know for sure if I would try that one again but yes, it can be done.

Do not ride with a death grip. And if you can't much ride a bike quit making fun of those who can. Goodbye.