I own a lancer with tires that may have run almost 5k kms (ceat accelere). Around 3 months back i went for wheel balancing and alignment and noticed a steering wobble immediately after that, the reason given to me was that one of the tires has an uneven surface which will even out in some 5k kms. But i never felt that happening, the steering used to be wobbling especially at slow speeds and need to be held onto to prevent it from wobbling. I went back to the same guy and got the wheels rotated back but to no avail though the wobbling reduced than before (he also told me at the same time that my steering tie-ends or what ever need to be replaced). recently i got the car serviced and was told that it is a tire problem and not the steering one but was asked by the service centre guy to get the faulty tire/ tires to be repaced as it will harm the steering column in the longer run (but ironicaly he could not spot which one is the faulty tire with uneven surface)
Please let me know what to do? Does it makes sense to get all the tires replaced when they are relatively new and can still be worked aroud for some time? Please advice how to get the faulty tire spotted so that i can get it replaced

rather than spending to replace all 5 sets
Thanks!!!!!