Out of interest, why don't you still have the SMT? I quite fancy one of the 890 SMT's subject a test ride.
Also, the BMW S1000...that engine can be exciting but you've got to keep the revs high which (on the S1000RR at least) can be a problem because it does over 100mph in first. That bike came into it's own over 120mph.
I bought the SMT as a tourer. I wanted a proper adventure bike, but at the time (2014 I think) that really meant a Multistrada, a KTM 1190 or a GS. They were all too much money so I bought the SMT as a sort of pretend adventure bike on the cheap. I test rode a 990 Adventure but it was too off-road focused for what I wanted.
But the SMT isn't an adventure bike, it's a giant supermoto. It wasn't that comfortable for distance riding, there wasn't much room on it and the engine begged to be ragged all the time so it felt busy. I sold it to buy an 1190 a couple of years later when used prices had come down. Ideally I'd have kept them both but that wasn't an option at the time.
The SMT was a superb back lane scratcher and that's really what it's for. And unlike most adventure bikes it had 17" wheels both ends so it could be shod in proper sports tyres. The WP suspension on that generation of KTMs was top-notch. As good as factory Ohlins and better than subsequent WP units on later KTMs (the same suspension shop rebuilt and set up the suspension on both the SMT and the 1290 Superduke I bought later and he commented on how much cheaper and nastier the SDR's units were compared to the SMT).
KTM's suspension is back up to scratch now. I think they just did a bit of cost-cutting with the gen 1 Superduke. I doubt you'd have any complaint with the latest models. If the 890 SMT is half the bike that the old V-twin was it will be a corker. The original was heavier but it had more power and torque once remapped. After uncorking mine with a DNA airbox Leo-Vinci cans, binning all the emission control gubbins and getting it custom mapped, I was getting 120 bhp and 78 ft/lb of torque. It was punchy as hell.
Personally I can't feel the love for the parallel twin KTMs. They just don't have the character (that word again) and instant punch of the LC8 V-twins. Worth a test ride though. A long one ideally.
As to BMW's four, I test rode an S1000XR years ago and nearly hit an oncoming car when I had to pull out to pass a vehicle on the side of the road. A car appeared round a bend, I hit the gas at around 5000 rpm to squirt clear and get back onto my side of the road and absolutely nothing happened. I had to knock it down two gears to find any propulsion. Admittedly my bike at the time was a 1050 Speed Triple which had much more midrange torque, so my mindset was still in triple mode. No doubt if I'd ridden the XR for longer I'd have adapted my riding style to the power delivery, but I didn't like the engine. It felt like I was thrashing the guts out of it all the time to the point of abusing it. 7000 rpm felt and sounded like 12,000. Some people like that but it wasn't for me. It was very buzzy as well.
I think that's a peculiarity of the BMW four. Not all I/L fours are like that. The cross-plane Yam and the Honda Fireblade feel far less over-worked to me.