You wanted a M98 and you now got one so have fun. First thing is to strip it down and clean off all the grease, dirt, and grime. Put it back together and have a reputable gunsmith take a look at it and check head space, setback in the bolt lugs if any and the bolt face, etc. If all looks good, get a rear sight and some ammo and go shoot it, and then you decide where you want to go with it.
As to the economics question, if you have the discretionary funds to do what you want with it, then do it. I'm not a collector to make resale/profit so I've never purchased a firearm new or otherwise based on resale value. I define what my personal intrinsic value will be for that particular firearm. Rarely will you ever sell a remodeled M98 milsurp gun for what you put into it dollar wise, but if you build it(or not) the way you want, shoot the hell out of it and use it the way you intended, who cares what you may sell it for later, its in your hands now and that's what matters.
I've got a 1903 MKI Springfield I inherited from my father and built up into a hunting rifle based on the so-called scout concept. Total expenditures was north of $1700 at the time. People have looked at me as though I've destroyed an antique collector gun or made some freak of a firearm. But over the last +- 30 years since that build I've killed dozens of big game animals, shot thousands of rounds during practice on paper, steel and rocks, carried it from the Montana plains to 9k+ ft. ridges freezing my ass off and crawling through alder choked ravines chasing critters and have enjoyed every minute of it carrying that rifle and I wouldn't have it any other way. That to me is more important than any financial gain I might make if I were to resell it.
