Wrong. The Corwin Amendment was introduced on March 2 and was ratified by the Senate on March 4. The Confederate Constitution was not introduced until March 11. The Corwin Amendment preceded the Confederate Constitution.
In addition to getting the timeline wrong, you are also wrong on the facts. The Corwin Amendment would have provided all the protections for slavery that existed in the Confederate Constitution with its ban on the Confederate Government imposing abolition of slavery on any state.
Of course, the Corwin Amendment was just spelling out explicitly what already existed de facto. The US Federal government had no power to abolish slavery in any state even if there had been widespread support for abolition which there wasn't.
Sorry, but your own timeline is wrong, as I have now spelled out in detail, twice, above.