Create a FAQs chatbot to use It in a Google workspace on-premise environment

Hi community,

I am investigating about the BEST solution to create a FAQs chatbot to be used in a Google workspace on-premise environment, for instance, to be used on. Google site, Google chat, …

I have heard about Dialogflow (but cann’t be integrated on an on-premise environment), RASA, BotPress, … Could you please give me recommendations about what the BEST choice and how i can develope and I would appreciate a lot an example of code.

Thank you very much on advanced!