So i read that Mew can do a pretty good job as a striker against Latios and gang. Decided to give it a go myself.
Mew 5/5 5* 0/20 – Power Flux 3
Torterra 2/5 0/20 – Escape Artist
Alakazam 2/5 0/20 – Vigilance
Arguably it was a team effort bringing Latios down as Torterra and Alakazam did heaps of damage also. Mew was there to debuff and dps simultaneously while Torterra buffs defense and sync after Mew. Alakazam gets first sync to Mega evolve and boost some speed followed by Mew to gain excess to Blizzard. By the last phase Latios was melting.
This is by no means an optimized run, just a casual test. The great thing about this game is that none of the battles requires specific strategy with specific sync pairs. That means we can always experiment with the pairs that we love^^
Have fun experimenting~