I tried going to that link and it wouldn't go thru. Can you add plug ins to ddp4 like luminar ai?
No, that cannot be done. You could use DPP to do your RAW conversion and do as little or as much image correction as you wish in DPP and then export a TIFF to other software.
"I will buy a new camera first."
You will need that camera or another Canon camera serial number to d/l DPP4. The latest version of DPP4 is very good and it is free. It is well worth your time to learn how to use it.
This is what you want. While there have been some changes to DPP since this was published, the tutorials cover all the basics you will need to become fluent and comfortable with the product. It has helped me a great deal.
07/31/2023: New firmware updates are available.
05/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
04/20/2023: New firmware version 1.4.1 is available for EOS R3
03/30/2023: New firmware updates are available.
2/07/2023: New product announcements!EOS R8 EOS R50RF-S55-210mm F5-7.1 IS STMRF24-50mm F4.5-6.3 IS STMRF15-30mm F4.5-6.3 IS STM