Neuhaus, Musiala, Baku, Moukoko, Nmecha for example. There are also better "senior" players than Amiri or Kruse. E.g. Boateng, Reus or Dahoud didn't make the EC, heck, Brazil and Spain are even bringing players, who played with the first team this summer. Their clubs must love that.
Isn't Neuhaus 24, born in 1997? Oh wait Henrichs is also born in 97 and playing. Then yea Neuhaus could have played. I'll give you have Baku as well, though Nmecha I'm not sure how great he is and Max Kruse is playing as a striker and he's a really good player himself (maybe not as a lone striker though).
Regarding the over 23 players, I don't think any team regularly send their best players to fill that role. It's usually taken by players who aren't the most important players for the national team. I biggest player I can remember to play in that role was Neymar in 2015 but that was also because the Olympics were in Brazil.
Germany has been pretty succesful with those subpar teams lately though...
U21 Euro 2015 semi-finalists
Olympics 2016 finalists
Confed Cup 2017 winners
U21 Euro 2017 winners
U21 Euro 2019 finalists
U21 Euro 2021 winners
They were always overachieving with those average squads. This feels like the time they finally get shown up but you never know...maybe they scrape through to the next round and then manage to surprise us again.
Yea we've seen the 2017 U21 winners regress. Other than Gnabry, no other player from that squad has become a regular for the national team yet. Amongst the current winners, I don't see a lot of potential as well. Wirtz is of course a standout but then it's a bunch of decent players in Nmecha and Baku.
You compare them to the 2009 U21 winners and there is a stark difference even considering what they had achieved by then. Ozil was a key player for a team that reached the UEFA Cup final and won the DFB Pokal. Boateng had played in the semi final of the UEFA Cup that same year, Howedes and Neuer had a couple of seasons in the UCL, where they reached the latter stages, Khedira had also won the league with Stuttgart. This is excluding Hummels who has a great 6 months with Dortmund before that.
The talent of those players was clear to see even before they won the U21 title, I just don't see anywhere near that amount of talent in the current crop of players. The group of players with Brandt, Draxler, Dahoud, Sule, Goretzka, Tah etc also looked really talented but a number of them haven't fulfilled that potential.
Maybe I've just become more cynical with age but yea I think the last good youth group we had was the Goretzka batch and don't see a lot of talent in the next bunch.