It seems you disabled Google app on your device which disables Speech Recognition engine as well.
Some more info here:
I ended up going into PlayStore and looking for “Ok google” and I found that Google LLC was disabled. I enabled it and Speech Recognizer started to work again.
On Samsung S9 one can disable the Google application, and that will in turn disable the STT service. Found out the hard way.
https://stackoverflow.com/questions/45950605/isrecognitionavailable-return-false-on-android
https://support.google.com/websearch/answer/2940021?co=GENIE.Platform%3DAndroid&hl=en