Have you tried the save file method? Did you get a shadowban trying to force the old trainer? Share your experiences below (but don't ask for download links—they don't exist anymore).
If you're on the lookout for a reliable trainer for "Call of Duty: Black Ops Cold War" on PC that addresses or circumvents the "fling" issue, here are some points to consider: call of duty black ops cold war pc trainer fling patched