OP,
Your choice of the RX-V581 is a good one. Whether you know it or not, that's the least expensive Yamaha AVR that supports all the latest tech - Atmos, DTS:X, HDCP 2.2/UHD passthrough, etc. If you don't need Atmos or DTS:X, you can step down to the 481 and save some money. If you go lower to the 381, then you will lose the MusicCast feature, which is really kickass. It's basically Sonos, but more flexible and less proprietary. If you jump up to the RX-V681, you'll get dual, independent zone control which can also be really nice.
This is perhaps really obvious to you or not at all - no judgment intended - but if you are buying an AVR based upon power output, don't waste your time. Watts/channel and THD is a completely meaningless venture unless you consistently listen to music/movies at or above reference volume with speakers that are not very sensitive. 95% of all speakers will be louder than is comfortable with just 30W of power.
For your listening environment, I would highly recommend that you stick to a stereo configuration, whether with two speakers or a single soundbar. Like you said, surround sound is only beneficial if you're in the sweet spot, whereas stereo is a bit more forgiving (depends more on the speakers used). Fewer speakers also means fewer wires, less complexity, etc. You'll also find that in many cases, good stereo placement (or a good soundbar) can provide an adequate surround illusion.
FWIW, I've been buying Yamaha almost exclusively since 1993 and never had a single problem. That said, there's nothing inherently bad or good about most brands. The switching/amplification process was perfected about 100 years ago and not much has changed in the AVR world from that perspective. Really it just comes down to features/software/usability. Denon and Yamaha are both pretty competitive when it comes to software/app control over the network. Yamaha's recent MusicCast system has proven to be incredible, however. I generally favor the DSP of Yamaha, but that's mostly because it's what I keep buying so I'm used to it.