I just installed CNC again, after 2 years. Took me a bit to remember how to set it up, but i managed to do it. However im playing KW, but hopefully it should be the same for RA3.
1. Install CNC Online
2. Make RA3 shortcut
3. Install CNC Ultimate collection fix (https://bibber.eu/do...tion-launchers/)
4. Hook the game in CNC Online
5. Launch from the created RA3 shortcut, it should open CNC Online launcher and then just click on RA3
Like i said, this is for KW instead of RA3, you can try it i guess, hopefully it will work for you.