Rate my Gen 8 OU Team

Question

Regieleki @ Magnet
Ability: Transistor
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
- Substitute
- Rapid Spin
- Thunder Wave
- Electro Ball

Aegislash @ Leftovers
Ability: Stance Change
EVs: 252 HP / 4 Def / 252 SpD
Calm Nature
- Shadow Sneak
- King's Shield
- Steel Beam
- Toxic

Blissey (F) @ Leftovers
Ability: Natural Cure
EVs: 252 HP / 252 Def / 4 SpD
Relaxed Nature
IVs: 0 Atk
- Wish
- Blizzard
- Counter
- Seismic Toss

Slowking-Galar @ Toxic Orb
Ability: Regenerator
EVs: 252 Def / 252 SpA / 4 SpD
Quiet Nature
IVs: 0 Atk
- Trick Room
- Trick
- Venoshock
- Psychic

Skarmory (M) @ Leftovers
Ability: Sturdy
EVs: 252 HP / 252 Def / 4 Spe
Bold Nature
IVs: 0 Atk
- Roar
- Spikes
- Stealth Rock
- Protect

Corviknight (M) @ Leftovers
Ability: Mirror Armor
EVs: 252 HP / 252 Def / 4 SpD
Impish Nature
- Light Screen
- Body Press
- Iron Defense
- Iron Head

Comments

The Pokemon are not bad, but the sets are totally not good. Electro Ball + Thunder Wave / Agility Regieleki is a big gimmick, not giving Defog to Corviknight and having Rapid Spin instead is bad. SpD Aegislash is uncommon, but the issue is that Steel Beam is worse than Shadow Ball / Flash Cannon  because it's a defensive set. Blissey does not run Counter, and Blizzard is too weak to be effective. Slowking-G is a AV tank, not a TR setter. Skarmory and Corviknight are not required on the same team, but generally the latter is good. The set's not that good and Pressure is better than Mirror Armor.

I'd suggest reading the https://www.smogon.com/articles/getting-started guide in case you're new to competitive, then know about the tier's usage of different Pokemon.