The wearing parts of the mechanism can be bought separately to refurbish the mechanism without renewing the whole cassette. It's time consuming but can be DIY.

https://www.newtis.info/tisv2/a/en/e...-roof/FgF5ZWi0

https://www.youtube.com/watch?v=EXUxdirwino&t=505s

https://www.youtube.com/watch?v=9aMReQPJElU

https://www.youtube.com/watch?v=rsfWzZ3z7yQ