You can make HSA contributions up to the tax deadline, so that would be April 18, 2023 for tax year 2022.
So if you make sure your employer is contributing less than the total allowed, you can then make up the difference by the filing deadline.
Making sure you haven't contributed any excess is important, and best taken care of as soon as possible. This is a big mistake for an employer.
Know, too, that you can pick your own HSA custodian or transfer funds to a different custodian. Fidelity, for instance, does not charge any fees and allows you to invest all of your balance. HSA Bank, though, holds your hand more. I've used both.
