This team is definitely an improvement over the previous one even though some of the choices are not the best. If you want to use a pokemon, you should take the time to look at its smogon analysis page. Since you are playing gen eight, just google '(Pokémon name) smogon ss' and click the first link that shows up. At any rate, I'll try to give this a go
This moveset is so gen six. You're better off running a moveset of Swords Dance, Earthquake, Fire Fang and Scale Shot with Yache Berry. What this set does is it ensures that the only ones who can wall you are Mandibuzz and Togekiss, who are basically non existent unless you're at > 1300 elo and that Rillaboom will be the only one that can revenge kill you. SpookyTerrain's idea of lum is not a bad one but the opportunities provided by yache is simply too good. Also, use a Jolly nature. There is nothing more depressing than seeing a Garchomp get outspeed by Urshifu
Ahh the best metal birb ever. Iron Defense/Body Press isn't a bad set but it's inferior to its standard spread because one of Corviknight's biggest perks is U-turn. In this meta, it's usually better to leave dealing with threats like Garchomp and Kartana to ones who are guaranteed to take them out. Instead, just give it a moveset of Defog, Roost, U-Turn and Body Press
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Atm, Bisharp sucks real bad. It's reliance on Sucker Punch as priority makes it far too easy to take advantage of. If you really want a dark type, just use Weavile. It's one of the best threats in the tier and more importantly, it works very well with yache Garchomp. One of the mons that Weavile is almost never gonna break through on its own is Buzzwole but with yache Chomp as a teammate, Garchomp can get rid of it for Weavile and in turn, Weavile can sweep in the event Garchomp is unable to
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Swampert isn't exactly a great mon in the tier right now. It faces stiff competition from Lando as a utility ground type and from Pex as a water type. Instead, use Pex in its place which is basically a glue mon. It can stuff a lot of offensive threats and has access to the ever irritating knock off
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On this team, getting rid of metal birbs and metal durian isn't an issue. Both of them straight up die to Garchomp so there is no reason to use Magnezone at all. Instead, use Landorus in its place since it can serve as a Tapu Koko check, Garchomp buffer and Heatran switchin all at once
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Finally, your team still needs immediate power so why not use Kyurem. It's one of the biggest threats out there because STAB ice type is really nasty. Also, Dragonite sucks. It requires too much support to pull of and Garchomp is a far better option as a sweeper. I'll even make this Kyurem set much deadlier since it will still have a stab ice beam that threatens half the tier
Here is the paste. Do not tamper with the evs on Corv and Pex. Those are the standard ones that allows them to handle the metagame. Mix Pex allows it to handle Dragapult while the standard Corv allows it not to die to specs Lele's psychics, most of the time anyway. The team is vulnerable to specs Kyurem so your main goal should be to knock off its specs and leave it walled by Corviknight