As for a good cutoff point in past models, it really depends what you want the new receiver to be able to do. Your planned new TV is 4K & has HDR so you definitely want something with 4K upscaling/passthru & HDR capabilities.
You mentioned your boys love sounds flying overhead, but do you have or intend to add atmos speakers (in-ceiling or upfiring)? That will definitely improve those effects, but isn’t an option for everyone due to room and other limitations. If you want to add atmos, even if in the next few years, then you should get a receiver that is capable of it. If additional atmos speakers aren’t ever going to be added then don’t worry about having the ability to process atmos formats.
Streaming capabilities, multi-room audio, and the dozens of other features may or may not appeal to you, but those type of features can easily be added while video and audio processing are the real bread & butter things where you get what the receiver has and have more trouble working around or adding if it’s missing. Aside from getting 4K, HDR, & atmos (if desired), get the most power output you can afford.
As for if the speakers make sense, if you don’t like the sound then they might not be for you. I haven’t heard your speakers, but bigger towers tend to have more oomph than wall-mountable...that said, your room or your significant other might require in/on-wall speakers and nothing you can do about that.
You mentioned your boys love sounds flying overhead, but do you have or intend to add atmos speakers (in-ceiling or upfiring)? That will definitely improve those effects, but isn’t an option for everyone due to room and other limitations. If you want to add atmos, even if in the next few years, then you should get a receiver that is capable of it. If additional atmos speakers aren’t ever going to be added then don’t worry about having the ability to process atmos formats.
Streaming capabilities, multi-room audio, and the dozens of other features may or may not appeal to you, but those type of features can easily be added while video and audio processing are the real bread & butter things where you get what the receiver has and have more trouble working around or adding if it’s missing. Aside from getting 4K, HDR, & atmos (if desired), get the most power output you can afford.
As for if the speakers make sense, if you don’t like the sound then they might not be for you. I haven’t heard your speakers, but bigger towers tend to have more oomph than wall-mountable...that said, your room or your significant other might require in/on-wall speakers and nothing you can do about that.