I believe your problem lies with the Pokemon you're using as well as potentially their ivs and evs. Toxepex is a lot better on the switch in to an opponent that can't really touch it to set up, you need something that can immediately deal a large amount of damage and cover your threats. Aegislash is fine but using swords dance is not advisable. Consider that you won't be able to set up and sweep with a Pokemon without a particularly effective priority move or the ability to block incomming priority or deal with resistant threats. Also both your Pokemon are weak to ground. A good core although I can't say specifically because I didn't get the game, however assuming it's like the sun and moon battle place use this as a guide to build a successful team for it:
First Pokemon: Sweeper, you want to have something that can deal a lot of damage and fast, give it strong priority settup and coverage. Ice punch, earthquake, drain punch and knock off come to mind as good all round coverage moves, while dragon dance is a good settup move. Here you want something with a good typing, attack stat and speed stat. Potential items are focus sash but don't use it for setting up as priority is a thing, and a choice item, but build your sets accordingly of course
Pokemon 2: this is where you want a coverage based sweeper, don't worry about settup on this one as you specifically want it to be used on the switch to cover your previous Pokemons weaknesses and take out that threat. Abilities that nullify the damage you're afraid of or particular typing / natural bulk are key. as well as a priority STAB move of the type your first Pokemon struggles with. Do keep particular Pokemon in mind though when making this Pokemon, if both this Pokemon and Pokemon 1 can't hit something in particular you may be forced to stall it out which can be particularly dangerous if versing a strong sweeper or wall
Pokemon 3: this is where your toxepex like Pokemon can go, the strong bulky wall or pivot to stall out particular machups that relly on sweeping at a cost or stalling with poison, flinch or the like. Poison and flying types are particularly good at this, poison for it's immunity to poison and flying for it's immunity to earthquake. Pokemon with regenerator are particularly useful if you don't intend to stick around after weakening your opponent. Aegislash is also kind of good for this but consider it's vulnerablity to earthquake or relentless attacking and the weaknesses of kings shield. In-game people are not real people so they just love to headbutt kings shield but at the same time they can very easily be hiding stupid moves that would only be good in this particular situation.
So try to build a team based off those ideas, it's what I've used to win it in previous games. And a few other bits of advice, you're omniscient so uh
There are his teams and movesets, if you cant confidently say what you would do against them then you may need to rethink your strategy.