Abandoning the factory stock doesn't need to be the first choice. If that stock were my problem I would be inclined to see a good gunsmith who specialized in restorations and stocking rifles. There is a lot meat at the wrist and the side of the receiver that can be glued and reenforced.
Steve Balleck was known to work magic on replacement wood on some of his 1920s back in the day. I'd drop him a line at the 99 FB site.
Yeah, thats a clean looking stock and a clean crack. Seems to me that someone crafty with glue or epoxy and clamps should be able to make that crack pretty much go away, or at least out of mind.
Of the early 1920's there are more broken stocks than not. It looks like all the pieces are there, I would contact Clint Meier. https://cgm-gunstockcheckering.com/
You can check with Gunstocks, Inc. online. I just bought a walnut buttstock for my 1927 99F takedown in 30-30. They also have forestock and buttstock sets.
I agree that crack repair looks very doable, if it turns out unacceptable to your standards, it becomes a good template for someone to make a copy for you.
I'd be happy to do the repair for you, ..I can offer that I won't let it get any worse, and it will pass the social distancing test (looks fine from 6' away!)...
Here's one that's on the bench now, a Win 75 sporter;