EEZstudio slow FPS when updating slider widget VS same slider from Squareline

[TKCAJS]

Don't know if this is a bug or more of a general query.

I decided to have a try making screens with EEZ as my experience with Squareline has been problematic (some widget items don't work properly or crash the ESP32) and workarounds are not ideal.

In squareline I have a screen with a slider which is used as RPM gauge, basic indicator colour with a png for the knob and no background. slider value is updated with a changing RPM value. It works ok.
There are also 4 other small bar widgets all updating separately with simulated values.
Makes approx 27fps on ESP32 with 800x480 RGB display (cheap yellow display).

So - I deleted all the Squareline files from the project in VScode and replaced with EEZstudio files, but just the RPM gauge same size above and kept it simple with no knob. Same value updater, Nothing else on screen.
Only makes 18fps.

No other changes between the two projects (lv_conf.h) etc.

So the question:- Is there something else I need need to do to get EEZstudio properly configured (other than just swapping out the build files) as it's clearly not optimised? I nievely assume that both Squareline and EEZ just make the same LVGL calls and performance is down to the LVGL config and the underlying hardware.

Thanks for any input!