Djokovic 2.30
Federer 8.00
Nadal 8.20
Zverev 9.50
Tempted to place a bet on Zverev, nice odds, I believe Federer is done physically, same for Nadal (will too rusty at least), while the favorite is Djokovic I think it's time for Zverev to step up and go far, maybe capitalize on an early crash for Nadal or Federer.
Zverev won the ATP finals while he was at odds 20 before the tournament, it's time to back him to win a slam.
Any constructive opinion welcome.
I would consider Zverve a risky but worth taking bet, if you believe he can cause an upset. In my personal opinion Nadal would be coming after a long injury break and he'll be at his best to keep his number one status intact. I'll agree with you on federer I don't expect much from him, he's way past his peak. I would however not consider Djokovic out of the equation, as he will do all to become number one again. I would advise you to check their injury status before you place a bet.