How to print / echo / debug RateRequest properties in custom shipping method

I’m able to use this city dropdown plugin successfully.

Now I’m trying to call shipping vendor API in my custom shipping method.

Can anyone help me how I can print / echo / debug the destination in VendorModuleModelCarrierCustomCarrier -> collectRates(RateRequest $request) method ?

I’ve tried showing the RateRequest properties following this answer with :

• echo $request->getDestRegionCode(); or $request->getDestCity();
• debugging to browser console
• Logging the variable to debug.log / system
• $this->debugData($request->getDestRegionCode());

but still not visible , and the application mode has been set to developer as well previously.

Any help is appreciated. Thank you in advance.