I was under the impression that setting the default level to 100% would cause the on button to set the light to full brightness, regardless of whether the switch is currently on or off. This assumption is based on a reply from Eric in this post:
If thats not how it works though, I think @BertABCD1234’s solution is the next best thing. Pressing the on button 1x, even when the light is already on, should still send the scene command. If your hub supports scenes, it can then send a command to the light to set brightness to 100%.
Of course, this only works if your hub supports scenes and you are using a red series dimmer.