Hi, welcome to the forum.
We are now up to ggplot2 v3.4.3. It looks like aes_string() is no longer supported and likely has been superseded by something new.
Probably the best thing to do is provide some code and sample data that will show us what you are trying to do. Someone should be able to show you the new or alternative way to get the some results
Have a look at FAQ Asking Questions.
A handy way to supply some sample data is the dput() function. In the case of a large dataset something like dput(head(mydata, 100)) should supply the data we need. Just do dput(mydata) where mydata is your data. Copy the output and paste it here.