It's a good start but still needs a lot of work to be complete.
First off, I would use iMac 15,1 instead of 17,1 as you have a Haswell
4790K, the exact same CPU as the iMac 15,1 used.
You don't need the DSDT.aml file when using OpenCore. The guide specifically says that.
View attachment 529576
When you have the two required .aml files in the ACPI folder, they must be declared in your config.plist.
Here is where they should show up. You could us Proper Tree's snapshot feature to add them.
View attachment 529577
Also please delete the Warnings 1-4 as they are not needed.