I see a lot of confusion on the topic so I thought I'd clear it up.
Yhach is powerful and Ichibei and Yama are both powerful but these are the facts
Ichibei has the power of Darkness, the power to cut the name of the person in half, cutting their powers in half as well. He can also give out a new name distributing the power of another being or creature which will in all situations be inferior to the opponent such as a black ant.
Yamamoto has the power of Fire, he is basically destruction incarnate, Yamamoto has nothing to elaborate on. If you are cut by his Bankai you are automatically erased from existence. His Bankai can resurrect the dead, his flames of defense make all attacks null void and his attacks result are inescapable.
Yhwach has the power to reincarnate, heal and bring back his own powers. Ichibei cuts and removes powers, Yamamoto erases your entire being into existence hence why Yhwach admitted that Yamamoto is the only one who can kill him.
Conclusion: Yama-Jii can eradicate from existence, Ichibei can take away powers, Yhwach can bring back powers. You do the rest. It's just a case of match-up, Yama could get his powers cut in half by Ichibei but Ichibei lacks a final death blow to deal with Yhwach. Yama can potentiall kill Yhwach but Yama can lose his powers and be killed by Ichibei.
Yhwach > Ichibei > Yama imo
Yhach is powerful and Ichibei and Yama are both powerful but these are the facts
Ichibei has the power of Darkness, the power to cut the name of the person in half, cutting their powers in half as well. He can also give out a new name distributing the power of another being or creature which will in all situations be inferior to the opponent such as a black ant.
Yamamoto has the power of Fire, he is basically destruction incarnate, Yamamoto has nothing to elaborate on. If you are cut by his Bankai you are automatically erased from existence. His Bankai can resurrect the dead, his flames of defense make all attacks null void and his attacks result are inescapable.
Yhwach has the power to reincarnate, heal and bring back his own powers. Ichibei cuts and removes powers, Yamamoto erases your entire being into existence hence why Yhwach admitted that Yamamoto is the only one who can kill him.
Conclusion: Yama-Jii can eradicate from existence, Ichibei can take away powers, Yhwach can bring back powers. You do the rest. It's just a case of match-up, Yama could get his powers cut in half by Ichibei but Ichibei lacks a final death blow to deal with Yhwach. Yama can potentiall kill Yhwach but Yama can lose his powers and be killed by Ichibei.
Yhwach > Ichibei > Yama imo