ONLY contributions before Dec 31,2023 can be deducted on 2023 T1
https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/first-home-savings-account/tax-deductions-fhsa-contributions.html
Amounts that cannot be deducted
Contributions that cannot be deducted for a previous year
You cannot deduct the following contributions on your income tax and benefit return for the previous year:
Contributions you make to your FHSAs during the first 60 days of the year cannot be deducted on your income tax and benefit return for the previous year, unlike contributions to an RRSP.
Example – Contributions in the first 60 days of the year
Contributions that cannot be deducted in any year
You cannot deduct the following contributions on your income tax and benefit return for any year:
Contributions made after the first qualifying withdrawal cannot be deducted on your income tax and benefit return for any year.
Example – You may not deduct contributions after the first qualifying withdrawal
An excess FHSA amount you designate as a withdrawal cannot be deducted on your income tax and benefit return for any year.
Example – You may not deduct any excess FHSA amount you designate as a withdrawal
Any contributions to your FHSAs that exceed your lifetime FHSA limit of $40,000 cannot be deducted on your income tax and benefit return for any year.
Example – Deductions after contributing more than the lifetime FHSA limit
If you have an excess FHSA amount after your maximum participation period has ended and you have not reached your lifetime FHSA limit of $40,000, you may not be able to deduct all of your unused FHSA contributions. This is because after your maximum participation period has ended, your annual FHSA limit is $0.