Maybe Klefki can utilise Eject button to be a good slow pivot.
Klefki @ eject button
Ability: Prankster
Bold Nature
252Hp / 252 Def / 4 spD
-Thunder Wave/Torment
-Light Screen
-Reflect
-Recycle
The idea is to be a strong pivot that assists a setup sweeper heavily, and is designed to be used with any substitute-using sweeper. On the first use, your aim is to set up the correct screen before being ejected. This gives a sweeper an immediate free switch-in, and it should be able to get behind a substitute with the appropriate blocking screen the next turn.
On the second switch-in you have a different role- your eject button is consumed so not every hit will switch you out. This now gives you the chance of choosing to slow-baton pass to an ally by using recycle on the turn you want klefki to switch out. This means klefki will absorb a hit before passing out to an ally, giving them a free switch.
I added torment as an option instead of thunder wave. I think torment is a strong move to be able to switch certain pokemon into, especially if you have any pokemon on your team with protect- for instance, speed boost sharpedo, yanmega or a pokemon like Vaporeon/Umbreon/Sylveon with wishpass and immunities to certain moves (water/psychic/dragon).All these pokemon can potentially dodge powerful moves aimed at them altogether, and either stall out the enemy with toxic+wish (for the eeveelutions) or just ohko an opponent without access to powerful moves for the speed boosters.
Edit: I thought I'd add some other examples of how eject button strategy can be useful since people dont use it much. Not in a condescending way I just figured it'd be good to just mention a few things.
When passing wish, it can be hard to get the wish to the low hp recipient without them getting hit and dying. Using eject button, you can switch in klefki to absorb a hit and get your wish recipient in safely.
When choice locked into a move and facing a pokemon you can beat if you had the option of changing moves, switch in klefki to absorb a hit and then switch back into your choiced attacker to continue the sweep.
Eject button blocks a pokemon from switching out with u-turn and volt switch if they use it. This is great because it helps break down frustrating voltturn cores (especially scizor, as klefki can easily absorb his banded U-turn with 4x resistance). That being said, klefki should probably leave absorbing rotom-w's volt switches to someone else.
If you get hit by a move boosted by Sheer Force, you wont be switched out. That makes landorus a solid counter due to bypassing eject button shenanigans, hitting klefki on its weaker special defense, and being thunder wave immune