So far I have used a module in Joomla 3 to enter and evaluate php code. In some modules I used modules anywhere with the context {module module title}. This worked great.

Due to the switch to Joomla 4 and the removal of this module, I rewrote the php code into my own modules using sourcerer. But now calling another module in this module no longer works. I always get the warning message: 0 syntax error, unexpected string content "", expecting "-" or identifier or variable or number.

I can't understand this at all because the same php code is otherwise correct and worked before. The syntax {module title='Modultitle'} or the php interpretation [module title=\"Modultitle\"} does not bring any changes or improvements. The error message remains.

Are there any known problems with using Modules anywhere through sourcerer? Where is my problem? Can you help me?

Nice try, but I have the problem in the same Joomla installation. The ordering of the plugins can therefore have no effect.