Mew - BEST QUICK - BEST CHARGE

DT/IB is also very great.

I'd be happy with that. I just know I'm gonna get Volt Switch and Bulldoze

Its situtational and dependant on what you wanna use Mew for. Me personally I like Blizzard for current latios|latias raids. TMs for Charge could take forever to get right move i i want because it doesn't cycle through them and you could get what you already had 10 times before you get what you want (somebody told me at a raid that it took someone 60 tries). Little more leeway when its comes to changing fast moves. Less moves and likely to more Fast TMs. Snarl is SE against pyschic so it would work for Latios|Latias as well as covering a wide range of other types. I like the way Frost breath Feels and looks better though so i might Tm fast move to see what i get. Theres not much difference in eps,Dps, between Snarl and Frost Breath so i depends on what i wanna use Mew for.
So I guess Maybe play around with moveset First and see if you like what its doing. *Also imortant to consider mews sats which are well balance,but dont really make or break it when compared other pokemon with simiular moveset typing.

I had poison jab|Dragon claw. Swithched my fast move and got frost breath in maybe 3 trys. (I wanted it or dragon tail). Use him in a few latios rqids today and love the way it felt. Might feel different about it in the future but for now im happy with it.

To each is own Thougg amigo