Retirement tax questions

I am also jumping in on this, for the 2023 tax year.  First year I've taken a RRIF distribution from Canada.

I have worked through the "canadian retirement" section under income, and then the foreign tax credit and form 1116.  BUT, while my Canadian taxes withheld (in USD) are over $300, after completing all the sections it tells me my foreign tax credit is a measly $66.  I thought all of the taxes withheld by Canada would be usable as a tax credit? (We do have other income from W2s and business >$200k, so the income limitation is not an issue).

What gives?  How do I get it recognize the full tax credit?  This will become a bigger issue in future years, as we both start taking larger distributions.

Thank you for any insight on this!