I had to look it up but it seems from what I read that a Y receiver is a TE that lines up on the line. And that F and H line up in the backfield one of them a bit closer to the line than the other. Both more like a fullback. I don't know how you can't call Sternberger a traditional on the line TE and certainly Tonyan lines up on the line almost all the time. We can count this game. Deguara may spend a lot of time off the line next year but I certainly don't think he is limited to that. It's not like you can expect a TE to block a pass rushing DE one on one. Even Mercedes cannot really do that and he has monster size. Thing is...he is not a pass catching TE. He gets open because they expect him to stay in and block. Going by size, I think we have Y tight ends. Sternberger is young and I guess he will add some weight. Basically, I think we are set at TE. Please pick this apart and show me what I said that is wrong, what you think we are lacking, why and what you would prefer.
There are four designations for various types of tight ends. I'm sure there are slight differences in definition depending on who you ask, but here is my best understanding:
The "Y" is what we think of as a traditional in-line tight end. But merely lining up "in-line" on occasion is not all it means to be a "Y." These guys do the heavy lifting in the blocking department, especially in the running game. A big differentiator of a Y is that they can be relied on to block defensive ends play-side. So you can literally run behind them. Lewis is a Y. Gronk at his height was an elite one. Nick Boyle of Baltimore is another fantastic example.
The "U" designation refers to traditional tight ends, who may spend the majority of their time in-line, but who lack the ability to handle front side blocking responsibilities. You can run with a U lined up in-line, but you probably want him to have back side responsibility, not front side. When I think of a U, names that come to mind are like Austin Hooper or Hayden Hurst. I don't watch those guys enough to be super confident in their roles, but that's the kind of profile.
The "F" designation refers to the guys that are basically big slot receivers. They're usually plus blockers when they're detached from the formation, but a liability when trying to block in-line. This is how Kelce is used most of the time. Others in this mold would be Evan Engram or Noah Fant.
The "H" designation refers to the guys that are lead blocking specialists. Kyle Juszczyk is the best pure "H" going right now, and we all hope Deguara can thrive in that role as well.
Now the lines between these types blur all the time. Just as you might say a certain receiver is a "Z," but on occasion they line up as the "X." When you call a guy a "Y" or an "F," it's just a way of saying what his role will be most of the time.
In my opinion, both Tonyan and Sternberger are guys who can fill "F" or "U" roles, but neither have the frame/power to be "Y" tight ends. However, Sternberger could get bigger/stronger and prove to be able to do it. But I would be surprised.