Natural selection doesn’t have intent. It has no goal. Just as water running downhill doesn’t intend to move so. It’s a process that occurs given the right circumstances.
There is, however, a pattern to the results the process produces. It’s a convenient consequence.
The process of natural selection can stop if you interfere with conditions it arises from - but that does not kill the process, as it can return as soon as those conditions return.
Are we affecting natural selection? Yes.
Are we killing it? No.
Another question:
Do we need natural selection to guide us anymore?
I don’t think so. We can understand the environment better than a slow blind process that entails countless amounts of death to power it’s cogs.
The environment we live in today, is far different than the environment that shaped our ancestors.
Are all our instincts that saved us in the past, relevant and beneficial to us in the present day? Ought we seek to preserve and reinforce them?
These are questions we can answer and respond to far more effectively than something that is blind.