... 2021 summer either in June or August, and planning to organize ... (we can meet up once or twice to share our thoughts ... /strategies/or just rant...). So, here are ...
... is when using "_not A or B_", the sentence sometimes mean ... a sentence uses "_not A or not B_", then it means ... literally "_not A **or** not B_".
... seeing a sentence "_unless A or B_", I am not sure ... ) not A if not P or not Q_