Save up to 60% off new Mountain Bikes - MTB - Motobecane Fantom 2729DS Disc brakes, Tubeless Compatible Rims

If this is the bike you are talking about --- it looks like a reasonable facsimile of a Santa Cruz Superlight - (I'm sure there are differences- but if you ride once a week - who cares) Install a race face narrow/wide chainring and a wider range rear cassette and you could ditch all the extra fluff

Should be able to take care of any riding you want to do in your area and the IMBA trail in KS(switchgrass? - IDK - its been a while) just south of you.

You mention kidneys and back issues --- that usually points to issues with bike fit and riding technique as opposed to the style of bike though -- I'm an old Clyde as well (44 y/o and am dangerously close to "SuperClyde" territory) and i dont have these issues on the rocky, rooted up trails i ride, but it took me a few rides to dial in my cockpit and bike fit after i tried a couple of different seatposts, stems and bar combos.

A 29'er, whether FS or hardtail -- will also steamroll over small stuff better due to the much longer contact patch with the ground - like the kind of roots that give you a short, sharp spike to get over