By the time you can afford Krell speakers, you’ll have AM radio ears.
This is the grim reality of high fidelity. It’s a race against declining high-frequency hearing.
Here is a very depressing pair of charts. Look at frequency perception at older ages.

Therefore, if you are over age 20, the first step to take in putting together a high fidelity playback system is to test your hearing. The Web makes this easy.
First, see what a group of mixed-age people can hear. If there were no females in the group, it would be even more depressing. Women retain high-frequency hearing for much longer than men do.
I know that my hearing has degraded over my many years of loud noises during my military career. I could not hear the high pitched sound at all during the "test".
It's particularly a bummer for those of us who do live sound mixing for Churches and other events. It's funny, because almost no women do volunteer audio work for Churches, yet they probably have better ears for it. But the good news is that when our wives complain we are listening to them, we can now blame it on our 'medical' condition!
I know what you mean, Chief. I went through Army basic in 1961. In those days no ear protection was worn on the firing range or anywhere else. I guess that was for sissies . The high-frequency hearing in my left ear is severely degraded. I kept my right ear pressed against the M-1Garand rifle stock to save it. Got a poor score but saved some off my hearing. VA denied my disability claim by the way.
Re: headphones, I have to think the best under-$50 value out there are Koss Porta-Pros. They’re lightweight ‘portable’ on-ear type phones that sound way better than they ought. Even with plastic driver elements they throw off a respectable square wave in lab tests. One drawback – they have a 80-100hz bass hump so they sound boomy to appeal to the kids.
After that Grado’s 60 & 80s for under $100 are nice. Their appeal is their clarity and forwardness. Perhaps best for pop or rock, but I still enjoy them with classical too.