Those warnings in the end You are trying to downgrade the product "" from version [3.1.1.4] to version [1.0.0.0]. Downgrades are not supported.ojs2: You are trying to downgrade the product "" from version [3.1.1.4] to version [1.0.0.0]. Downgrades are not supported. might be connected, have not seen those before I think.
You could check from your versions table what you have stored with version number 3.1.1.4 there. If you for some reason have something else that OJS itself with that version number.
The ojs2 in the error you asked earlier is not related. That is for some reason hard coded to OJS and shows up with every error. I think they have just forgot to change it to ojs3.
But yeah Alec might have other advice