I priced a 2019 R1250GS loaded for $23,000. That's $7000 more than a 2018 S10 but unless Yamaha makes significant improvements to the 2019 S10, the BMW GS is worth the extra cash.
Where did you price this mythical $23k GS? Try actually finding one for that price. Most dealers fully pimp them out and the price is closer to $30k. My wife's '16 GSA was $35k+ out the door. If you wanted a stripped down version you had to special order it and they
claimed it would be 6 months wait. I do see GS's advertised for sub 20k prices, just not so sure you can actually buy one for those prices.
Go ride the GS, then ask the dealer how much an aftermarket warranty is for 4 years with unlimited mileage. Add that to the price right away, if they will even sell you an aftermarket warranty. They can't sell you a BMW extended warranty, BMW doesn't offer them. They looked into it, but apparently decided it would lose too much money and never offered that product.
Though not as common, BMW is still suffering final drive failures. And drive shaft failures. And transmission failures. And top end failures. Compare that to the very rare CCT failures a few Super Teneres have had.
My wife's prior BMW cost more in repairs than it did to purchase new up to 80k until the engine burned up. The 30k after that, with a new, hand built, motor from the dealer, was pretty good. Thankfully the aftermarket warranty paid for most of it. The current one has a 10 year, unlimited mileage aftermarket warranty. That wasn't cheap. Around $2500 IIRC. We know better than to own a BMW w/o a good aftermarket warranty. We ride the bikes.