Can I ask the same question? How should I motivate myself to go with more difficult exercises?

Edward W.
Sure, first I would say to acknowledge you’re reason for wanting to do it in the first place. When the goal is clear it is easier to pass obstacles in the way of continuing that path. Secondly integrate them slowly if increasing weight do two of your regular sets then include the new higher weight. If trying higher intensity exercises mix them within your current routine to slowly adjust.