Decently safe amount of AES key derivation? I am encrypting my computer using Veracrypt. The default 500,000 derivations is quite slow, what would a "safe" balance be between security and speed? My password is more than 20 characters.
VeraCrypt tries each hash and cipher combination with your supplied password if PKCS5-PRF is set to auto-detection on the enter password screen, i.e. it will try all. It will work until one of them work. It can do this in parallel. In the end, if none is working it will inform you that your password is incorrect.

Change it to the PKCS5-PRF that you selected during the setting the volume, it will not test the others. That will decrease the time.

In the attacker's eye, this will slow them, since they have to try all for each candidate passwords during brute-forcing possible passwords.

Also, the 500,000 derivations is important against the password crackers. The higher the better and it will affect the attacker's time linearly. In recent years their capabilities are highly increased.