Well, the thing is that "system settings>keyboard (re: the backlight)..." is not available under the keyboard settings! Unfortunately this MacBook Pro is my only mac with Ventura. I can see in an Macbook Air (2013 running Big Sur) that there is a setting called "Adjust keyboard brightness in low light", but again, this setting is not available in 13.2.1.check (or try changing) some of the settings in system settings>keyboard (re: the backlight)...
I have tried "the usual" resets (SMC and NVRAM) and also started in Safe Mode, but nothing helps