Tasmiyyah On Fish
I think whenever the Quran is speaking about dietary requirements the thing under discussion is meat (barring alcohol which is technically a different subject). That’s why the passive verb ذُكِرَ is used rather than the active participle because the time when the name of God is mentioned is at slaughter and you don’t slaughter fish or vegetables. This is especially clear in 22:36
You interpretation has tk be supported by the Quran. For example in the case of safa and marwa allah used the exact wording u used without brackets ولا جناح عليكم أن تطوفوا بهما but this wasn’t used for tasmiyyah. As for just mentioning the name at time of eating imo that’s not a valid view because the passive verb ذُكر is used not the positive command اذكروا اسم الله حين تأكلون