Do you have a 6.5 CM? If not then that is not only your problem but your pathway to choosing to make this rifle a 308. I find that it’s often not that I am having a hard time choosing between two cartridges, it’s that I am not buying two cartridges to prevent me from buying just one and that the solution is just to buy two more rifles. Then after buying a 6.5 and a 308 I am still left with wondering and am suffering from buyers remorse, so I buy a 7mm-08 as well. Problem solved.
I know that feeling. At one time, I had three .260 Rems, a 6.5-284, a .280 AI, a 6mm Rem AI, a 6.5x47 Lapua, a 6.5 Creedmoor, several .308s, a .270 Winchester, a .30-06 and some others sprinkled in in the deer cartridge range. I've learned since to be content and mostly have .308 Winchesters for hunting along with a 6.5 PRC.