If you shoot it at all, take it easy on the original ones and use standard FMJ commercial ammo.
What type(s) of ammo they withstood during War time is of no meaning today as the guns are now collectors items and should be occasional shooters.

The originals will fail with a cracked slide at the locking lug cuts, (especially the right side) and also the junction of the 'hood' to the slide body. Wether it's design flaw that's coming out as round counts go up for these oldsters,, who knows.
Post war Walther mfg (late) knew about the problem & corrected(?) it with increased width dimentioned slide walls.
Collectors call those 'Fat Slide' pistols because of the greater width of the slide to increase strength. But it's only a m/m or so,,not alot.

The postwar P1 & P38 mfg pistols were cracking slides same as the older WW2 mfg pistols.

Few spare original WW2 parts, especially slides, to repair those and they are $$ when you find them.

Like Lugers, no use in beating them up just to put some rounds down range with it.

If you want to try a diet of +P, I'd suggest a Postwar P1 model, 'Fat' slide with frame reinforcement pin & new recoil springs.
Even then, I'd wonder about the longevity of the pistol.
Just my .02