Here is an example that showing how you can do.

Hopefully they have a vulnerability on the spin attack and the ultimate technique.
Unfortunately in the most of the situation, charging the ultimate technique is probably a very risky suicide tactics.
Therefore until you can catch the right moment, you gotta deal with the spin attack.

Also while the spin attack, it will act like the I-frame. The Alchemist's projectile attack won't hit you.
Also most of the enemy's attack won't hit you. It acts like a shield or a barrier for a short moment.

Remember this.

Spin attack - Strong Attack Combo

If your strong attack has gotten successfully hit right after the spin attack, they will either block it or get hit.

1. They have blocked your strong attack.

Now you can grab them 100% ( Watch out. You may get damaged from the projectile. )

2. Your strong attack has gotten successfully hit.

You will see that they're lying on the ground. Now you can perform the Wind Run - Flying Swallow combo. It will successfully hit 100%.

They have a specific weakness.

They flinch very easily.

- Shuriken will make them flinch.

- Slinding will make them flinch.

- Wind Path will make them flinch.

And if they flinch, they will most likely change their attack pattern, especially from the projectile pattern to the melee pattern.

Make them flinch as much has possible. You can lead the battle.

I hope this small tip was helpful for you.
If you liked it I will share another type of enemy's vulnerability and weakness.
Good luck!