I would run Excadrill for a variety of reasons. First, Excadrill will only be tolled 3% of its health on switch ins while Mr. Mime will be tolled 25% of its health, barring Heavy-Duty Boots. With Mr. Mime, if you run Heavy-Duty Boots, you have to be very careful on what you switch in to. With 5 common weaknesses, 50 base HP, 65 base Defense, and 90 base Special Defense, you will have to be wary of any Physical Attackers such as Zeraora. Hoewever, in no weather conditions, Mr. Mime Galar does have a benefit. It has more Speed than Excadrill, but that is what I believe is its only advantage. Now, with only being tolled 3% of its health from Stealth Rock, barring any Spikes, and an immunity to Toxic Spikes, it has a clear advantage over Mr. Mime. Now, with this, Excadrill has a much more diverse item pool to pick from. You could run Leftovers (Smogon says this) or Life Orb. However, Excadrill has 110/60/65 bulk which severely lowers its durability. Now, while Excadrill has lower Speed, you can easily fix this with a Sand Setter to double Excadrill's speed. To add On to this, the most common Stealth Rock setter I see is Clefable. Luckily, Excadrill can take Clefable out with Iron Head.
Conclusion - Excadrill has an overall better typing and takes less damage from Hazards, barring Heavy-Duty Boots on Mr. Mime, to make it an overall better pick in my opinion. Excadrill also has access to Leftovers which Mr. Mime can't afford to run. All of this makes me conclude Excadrill is better overall.
Excadrill@ Leftovers
Sand Rush Ability
Jolly Nature
-Iron Head
- Earthquake
- Rapid Spin
- Stealth Rock/Toxic/Swords Dance. Your choice. I prefer Stealth Rock.
Hope this helps!
