Sniper Elite 5

This can be done very easily at the same time as the 'Reich to the Point' achievement, assuming you have unlocked the Berghof Guardhouse starting point. For reference, this is all the way North at a campfire to the right of the main road (near map end and extraction).

Simply start at the above-mentioned starting point with your rifle of choice (recommend silencing build and ammo but not necessary), start heading up the road towards the mansion but KEEP LEFT. A small gravel road veers left from the main road and if you follow this and then head left down the small trail near the house, it will bring you to a road that Hitler drives down. Hide in the back left bush or behind rocks until Hitler drives past and gets out. It takes about 2 minutes for him to get here after starting the level. Once he gets out and you have a clear shot, take it and backtrack to where you spawned to extract. Assuming you made a quick exit and didn't accidentally kill someone besides Hitler, both achievements should pop.

Of note, I had a problem with this popping at first and it seems that this mission would not let me restart while in the mission or load a save without voiding the achievements. Using mission select from the main menu fixed it.