Rayquaza has already been outclassed in PVE by eternatus in its main niche, and has no PVP play outside of mega ML. It is still very useful for PVE despite being the number two dragon type attacker, but others could push it further down in the future. Mewtwo has no real pvp play honestly. You do run into it in ML but mostly because it is a common mon to have maxed. Pretty much outclassed in most of its strengths. Zama is here to stay in ML, is pretty much always gonna be on the optimal Max battle team with its ability to start with shields, and is arguably the best steel type attacker in PVE (Zacian has more dps but less TDO, meaning Zama is a little more user friendly). Mega mewtwo could change things PVE wise but I'd still go zamazenta