As Alan says below: No, webform civicrm doesn't make use of the price set or contribution options (which is just a hidden price set) associated with the contribution page it's connected to.
You need to use the "Contribution Amount" field, then on the webform tab change it to a select box (radio) and enter the options you wish
Yes there is a bug here with it not having a 'no default' option. from memory you can do something like this. switch to static, untick the option that is beahving as 'default', save, then re-edit, set back to dynamic and resave. does that work for you?
Other things that may work depending on the component type
Open 'source' and in the YAML find in the ...