Typical use of insert from tkinter is:
text1.insert(5.5,'*')
I want to use:
for x in 10:
text1.insert(5.x,'*')
but I get invalid syntax.
The index is just a string in the formation of line.character, so you can use string formatting:
for x in range(10):
text1.insert(f"5.{x}", "*")