Effectively though, "any" opposition means any opposition that isn't downright stupid. That is, that's what it means in practice and is why the so-called strong solution is pointless and has no bearing on the solving of chess, if movements of the pieces are random blunders.
Who gets to judge what is/is not "stupid"? A panel of five GMs? AlphaZero? Optimissed? Once you arbitrarily omit broad swaths of lines from consideration, you open the conclusions reached to reasonable doubt.
The entire project of solving chess depends on rejecting bad moves and using good ones. A decent algorithm needs to be written, because I'm afraid that tygxc's "three grandmasters on ice skates" just doesn't cut it. Real AI needs first to be developed in order to write the algorithm.
Nice try.
Even discounting the ludicrous terminology, <<<weakly solved means that for the initial position a strategy has been determined to achieve the game-theoretic value against any opposition,>>>
actually means strongly solved (again in the ludicrous terminology), since any opposition isn't qualified to "any reasonable or effective opposition".
I suppose, as usual, it'll be another year before someone else understands what I'm saying. In the meantine, that time could be substantially reduced by junking the terminology as it stands and as it deserves.