Can I still enter an amount for an RRSP that was not submitted in 2022?

You can use Refile to add the RRSP contribution to your 2022 return. This FAQ tells you how: https://turbotax.community.intuit.ca/turbotax-support/en-ca/help-article/accounting-bookkeeping/filed-tax-return-still-make-changes/L992Trv7f_CA_en_CA?uid=lsw4btkw