I think it is necessary to build up some foundation of understanding with rhythm. I think that if someone is always mimicking teacher or Youtube, and trying to play rhythms by feel, there can be a big gap in understanding that displays as inability to sightread. The same as how youngsters can learn pitches by ear and fool their teachers into thinking they can actually read the notes, until they are asked to sightread something.
When I first started learning to read music, it started with pieces that have only quarter notes, half notes, whole notes. Only in 4/4 time to start with. And I would learn to clap and count: counting 1, 2, 3, 4 and clapping where the note should be played. A whole note would last the entire 4 counts, a half note would last 2 counts, but each quarter note lasts only 1 count. So there are a few patterns in 4/4 combining half note with 2 quarter notes. You have half note on count 1, quarter notes on 3 and 4. You have quarter note on 1, half note on 2, quarter note on 4. You have quarter note on 1 and 2, half note on 3. At some point I learned to read the equivalent rests, and added in the concept of dotted notes with the dotted half note, and did some pieces in 3/4 time. All of that came before seeing an eighth note.
So this is really basic stuff, but I think that is where it all starts. The smaller notes have the same relationships with each other as the bigger notes. The pattern eighth note followed by 2 sixteenth notes is the same relationship as half note followed by 2 quarter notes, except you are now subdividing the beat in 4 parts instead of having a rhythm that lasts 4 beats. So once you get to those rhythms, you need a way of counting that subdivides the beat also. When you've successfully executed a certain rhythmic pattern enough times, you can play it securely without having to count it out.
When you are really confident in the rhythms, you start to realize the literal rhythms aren't always exactly desirable and you can make certain notes in the pattern a bit longer or shorter according to feel after all. But I think to sightread rhythms, you need to understand and be comfortable with the literal note values and how they relate, so that you can deal with some less common rhythms that you run into.