

For me there really isn’t anything better in anime then moments like the one you describe in K-ON! I have that same picture up as the banner on !kon@lemmy.world. I think older anime do these tender moments better than the newer ones. For example Bocchi the Rock is quite forgettable to me, especially compared to K-ON! (I watched them back to back).
If you are interested in this type of stuff, you might want to check out the genre “iyashikei” (free translation: “healing genre”). The border with iyashikei, slice of life and cgdct is often blurred, I argue that K-ON! is indeed at least partially an iyashikei anime. It’s a bit of spectrum, most SOL will include some iyashikei but some have a much stronger emphasis on it. Other titles that may be of interest are Non Non Biyori, Hidamari Sketch and ARIA.
I did like BTR, just not as much as others praise it. Nice to hear that you already have Hidamari Sketch on your list, it’s underrated in my opinion. The animation style is also really unique.