It is possible, but very unlikely that your transfer case in not engaging the front drive shaft. It would be best to put the Sportage up on a lift so all 4 wheels are off the ground and then engaging the transfer case into 4 wheel drive. Then put it into gear and looking under it to make sure the front drive shaft is turning.
More likely is that you have a Frozen Hub.
I have had a couple of times with my front manual hubs when they would turn completely, but not engage on the shaft. It was just compressing the spring and not pushing the coupler onto the shaft. This is referred to as a Frozen Hub. I had to pull them off, clean them, and then relube them. Then it worked.
I recommend pulling them off at least once a year and cleaning then relubing them just to make sure this doesn't happen.
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White 1998 4 door KIA Sportage 4x4 w/Eibach 2.5 spring lift and TJ rear coils, 4crawler 1.5 body lift, Monroe Sensa.trac shocks, Bosch 4+ plugs, Eaton LSD, 31x10.5x15 BFG KM tires, 2.5 cat back exhaust w/SpinTech muffler