i came across below link which indicates that in step 4 overcontribution room is calculated based on Dec 31 date not the date 60 days later. Therefore, contribution made in first 60 days can be applied to previous year income or current year income. So contribution made in first 60 days of 2024 can be applied to 2024 income and not compulsarily needs to be applied to 2023.
https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/rrsps-related-plans/contribu...
