I know nothing about your planned rifle, except no matter how cool Mauser actions are, they are too soft for high pressure rounds....
BUT, the 6.5 Swede is not really a high pressure round. Rather sedate loads are 140 gr hunting bullet at 2650 FPS.....which is good for 500 yd deer performance because 6.5’s shoot soooo flat and straight.
When people compare to 30-06, they see similar mag capacities, harder to find ammo, but better long range performance...>300 yds. Also less recoil for similar performance.
When compared to 243 win/257 Roberts, it has better performance and Elk bullets available.
When compared to magnums, it holds more rounds, recoils way less and gives up just a bit of long range performance.
What is it poor at? In American rifles, it generally needs a long action....causing worse balance and longer action stroke. It has harder to find ammo, but not many fewer loads and not extremely expensive. It lacks much modern pressure data, so 260 Rem, 6.5-06, 6.5x284, 6.5 Creedmor are all a bit more size efficient......but you can load it hotter....that sounds contrary to your plan.