Has javascript gotten slow?

Some months ago I purchased an Owon vds1022i usb oscilloscope.
It uses a Java application for control and display.

Testing it with an old Pi2 running Bookworm and the default GUI
showed very nice performance, with the screen updating the Owon
control application fast enough that no delay was noticeable.

Now, several months and Bookworm updates later, I tried it again
and the oscilloscope application updates the screen roughly once
every five seconds.

Top reports about 0.6% user with the Java application not running,
but close to 30% with the java application running but just sitting
in the foreground with no inputs. 

Are there any known problems with Java on Bookworm?  I've tried
disconecting other usb devices and swapping keyboards, that didn't
help.

Is it possible to "roll back" the system by date? The initial tests
that worked well were done in early August, 2024.

Thanks for reading,

bob prohaska