I’d assume because you’re actively listening to music that you like and pick out. Maybe you’re singing along to it, or you’re actually listening to and interpreting the lyrics, tapping along to the sounds, you’re aware of every song that comes on. With radio music, it’s easy to passively listen to it, you’re not really fully aware of every song that comes on, maybe every now and then something plays that you recognize/like and you sing along to that, but then there’s probably a lot that you just tune out and ignore. It’s easier to “listen” to longer stretches of music if it’s just sort of background sounds you’re not as focused on.

When you listen to FM, the frequency is cut-off, at 15 KHz when I remember correctly. It could be that the higher frequencies make you tired.

The radio in my car was setup so bad I couldn’t stand any source, until I found the hidden equalizer settings. That helped, but the plastic dome tweeters in the rear speakers were the main cause. (I removed them completely)

There’s something about knowing there are hundreds of others listening to the same station at the same time that makes my local EDM station somehow more interesting than just shuffling the same playlist at home. Could your issue with albums have a social element similar to how watching a live sports match is just more exciting than the rerun an hour later even if you don’t know the outcome?

Also, I disagree with people saying that albums tend to be more boring because only the radio hits are good! I have many albums I like to listen to start to finish.

I think music tends to be exhausting when we’re not able to predict what will come next in the song. It requires us to put much more effort into learning the rhythm. Maybe the albums are just new to you, or a new style that you’re not used to?

Create a playlist of your favorite songs by genre. It would provide enough variety but still be cohesive enough not to distract you. Or rely on a streaming apps algorithm.