When you sit down to do something creative, it rarely happens in one go. It is normal for ideas not to come directly. It takes concerted effort.
Once an idea is there, getting it out into the world will also take time. Normally the first (of many) iterations isn’t perfect.
When you want to create, it is wise to go step by step. Every day.
Creativity is a Marathon, not a Sprint
When you sit down to do something creative, it rarely happens in one go. It is normal for ideas not to come directly. It takes concerted effort. Once an idea is there, getting it out into the world will also take time.