Who hardens our heart and blinds our eyes, God or us? (Isaiah 6:9-10; Acts 28:26; John12:40)

Each Gospel has an account were Jesus references Isaiah 6:9-10. Paul also references those verses in Acts 28:26. >*9 And he replied: Go! Say to these people: Keep listening, but do not understand; keep looking, but do not perceive. 10 Make the minds[c] of these people dull; deafen their ears and blind their eyes; otherwise they might see with their eyes and hear with their ears, understand with their minds, turn back, and be healed.* John 12:40 appears to be the only account that clearly says that God does the hardening (Every Bible on BibleGateway has translated it in this manner). >*He has blinded their eyes and hardened their hearts….* But I noticed that the original Greek does not have “God”, or the pronoun “He”.….they’ve been added in translation. The translation of Acts 28:27 does not attribute the hardening to God….it says that “they” have shut their eyes. >*For the hearts of these people have grown callous, their ears are hard of hearing, and they have shut their eyes* Again, the original Greek does not have a pronoun “they”, yet every Bible translates it in that manner. It doesn’t even appear that Isaiah Ch 6 clearly attributes the hardening to God. Verse 10 says *“make the minds of these people dull”*. Who/What makes them dull? Verse 9 could answer that question. It says people that listen, but do not understand….and people that look, but do not perceive. (Makes me think of fellow Christians that just go through the motions. I know….I used to be one). So I guess it’s a 2-part question. I do not study or understand Greek, beyond clicking on a verse and viewing the word for word translation. So, what is it about the original Greek that translators unanimously agree to add “God” or “He” to John 12:40, and add “they” to Acts 28:27? What is causing the hardening, God….or our own actions? The above translations imply both, yet they both reference the same verses in Isaiah. Shouldn’t the understanding be one or the other, based upon the understanding of the verses in Isaiah?