Hope you don't mind, but I've moved my reply onto the VAR thread.
This is actually something we can pretty much agree on. At the end of the day, a player is either onside or offside. Even if just by one millimetre. That can't really be debated. And nor do the PL have the power to change the offside law itself (eg back to the old "clear daylight" rule).
But it still comes to the PL as to how VAR is implemented in the PL. There's no reason why they couldn't decide to only use VAR to overturn offsides when, for example, the attacker has a whole foot beyond the last defender. (That's purely an example which I haven't put much thought into - the sentiment behind it is more what I am focusing on, ie that not every single offside necessarily has to be overturned by VAR. Instead, introduce a clear and obvious aspect to offside, like you say. They don't have to use VAR to overturn all incorrect offside calls - they are deciding that they will do that.)
Now if they ever come up with the technology which can give an instant offside decision, then great. All offside decisions become correct. But at the minute, spending three minutes trying to work out if someone is one millimetre offside is really not something I can particularly support.