The cost of a deleted Azure Key Vault with Purge Protection enabled

I made a mistake while creating my Azure Key Vault and didn't disable the "Purge Protection".

First question, is there a way to delete the keyvault or it is what it is ?

Second question, what are the costs to expect from a non purged Azure Key Vault for 90 days ?

All suggestions are welcome, thank you !

As mentioned in this MS Document,

purge' and 'recover' actions will count towards normal key vault operations and will be billed. If the object is an HSM-key, the 'HSM Protected key' charge per key version per month charge will apply if a key version has been used in last 30 days.

If you created your Key Vault in the Standard tier and generated an RSA key within it, it is typically not an HSM-protected key. HSM-protected keys are only available in the Premium tier

Once purge protection is enabled in Azure Key Vault while creation, you cannot disable it:

I have one key vault named demokv2105 with purge protection enabled as below:

You can temporarily delete this Azure Key Vault like this:

But these purge protection enabled key vaults will still be in soft-deleted state for 7-90 days and can be found here:

You can only delete those vaults permanently once days to retain period completes.