This may be a bit jumbled and have flow issues but anyways at the moment one of the more pressing mons I've found in this meta is Magearna, I've found it very hard to play airound at times especially given the offensive support it has from fairy and the defensive it has on steel. Starting on the support it has on Steel, the major offerings steel mono has to magearna is hazard stacking, with reliable deterrents to hazard removal to keep them on the field. Magearna pretty much thrives off of this kind of support, the hazards provide reliable chip damage on some of its bulkier checks such as Alolan Muk, AV Buzzwole, Chansey and Zapdos to name a few which can then help in securing a KO on these mons, a second bonus it has is due to it's ability with Soul Heart activating whenever something on the field faints including by hazard damage switchins. These two points can then combine into it's ease of set up, coming in on a mon that cannot properly check it forcing them out into their check which may already be weakened or maybe not at all allowing it to set up making it near impossible to check offensively as only the fastest scarfers such as Scarfninja have a hope of beating it out in terms of speed. From there it begins to snowball until it is uncheckable, I personally have played multiple games where the game will be evenly matched until magearna gets the set up and cleans especially against dark. This is just on the Shift gear set, further issues it causes is its lack of true predictability, it can viably run 3-4 z-move those being on its STAB's, All out Pummeling and even Gigavolt havok to punch through toxapex but it is impossible to know which of these it will run until it's actually being used unless you have a frisk mon. Of course there are other sets such as Assault vest which is extremely stubborn to take down not to mention extremely supportive to the rest of the team thanks to its typing and the ability to slow volt switch allowing it to easily gain momentum by forcing switches volt switching out and bringing in appropriate checks which can further help magearna's ability to clean later in the game. The sets arent without their cons however, as they can suffer from a 4MSS at times being unable to cover everything it would want to however it is only one mon on a team of 6 so those it cant check can easily be patched up by the rest of the team.
On to Fairy, Magearna isn't as much of a threatening mon as it is when on steel as its defensive support is lesser however in terms of offensive support it has plenty with Tapu Bulu and KoKo providing solid wall breaking support to punch through the mons that would otherwise harm magearnas ability to sweep such as Zapdos, Chansey and Alolan Muk without the need on hazard support makes it rather potent while unable to pick up boosts like it would on steel it doesn't always need them as much to make itself known in the game.
Of course this is not to say that magearna is good solely on it support, as it sports 80 115 115 Bulk with arguably the best defensive typing in the game with a respectable 130 SpA to back that bulk up means its no slouch, its speed stat while lacking at base 65 is still enough to outpace many scarfed mons as previously mentioned when at +2 which is never hard to reach thanks to the aforementioned bulk. Overall I just find Magearna to be a bit of an unhealthy presence within the meta game (I feel I am missing some things but I'll come back to it an add those in at a later point)
On to Fairy, Magearna isn't as much of a threatening mon as it is when on steel as its defensive support is lesser however in terms of offensive support it has plenty with Tapu Bulu and KoKo providing solid wall breaking support to punch through the mons that would otherwise harm magearnas ability to sweep such as Zapdos, Chansey and Alolan Muk without the need on hazard support makes it rather potent while unable to pick up boosts like it would on steel it doesn't always need them as much to make itself known in the game.
Of course this is not to say that magearna is good solely on it support, as it sports 80 115 115 Bulk with arguably the best defensive typing in the game with a respectable 130 SpA to back that bulk up means its no slouch, its speed stat while lacking at base 65 is still enough to outpace many scarfed mons as previously mentioned when at +2 which is never hard to reach thanks to the aforementioned bulk. Overall I just find Magearna to be a bit of an unhealthy presence within the meta game (I feel I am missing some things but I'll come back to it an add those in at a later point)