The screenshots that mentioned Mega(ATMEGA2560) were really helpful because I assumed this would automatically be picked up by Xloader. But I re-downloaded XLoader and saw that in their devices.txt, it showed the only two choices I kept seeing, the cc01 and cr03.
So, I figured why not give it a shot and added the following in that same text file
Rambo;atmega2560;stk500v2;115200;
Restarted XLoader, then I saw the Rambo entry I had just entered, and was able to flash it finally.
I think this is the fix. However, I did use arduino board
manager plugin prior to this. So that might have helped as well. Not too sure.
Regardless, thank you all again