You’d like to understand the various options you can use when starting bash, but bash –help is not helping you.
In addition to bash –help, try bash -c “help set” and bash -c help, or just helpset and help if you are already running in a bash shell.
bash sometimes has several different ways to set the same option, and this is an example of that.
You can set options on startup (for example, bash -x), then later turn the same option off interactively using set +x.