I got some controversial hot takes. Not going by vs battle wiki standards but by the series in verse scaling we can do this 2 ways. Raw power/Biggest Reiatsu level style or who would win in a fight. If we go raw power then
1.) Ichigo (Strong enough to one shot Yhwach even without his hollow or Quincy powers)
2.) Yhwach (Was stated to have surpassed the sealed Soul King before he even absorbed him in the manga, and in the novel it was stated that Yhwach had all of the Prime Soul King's power, and then he proceeded to absorb more like Ichigo's Quincy and Hollow powers etc)
3.) Prime Soul King
4.) Aizen (able to briefly scrap with Yhwach but on the losing end)
Then after Aizen there's a massive gap in power between the top 4 and everyone else
5.) Final form Gerard (was already stated to be the strongest Quincy in just his God Size form, then got Miracle amps from Shikai and Bankai Kenpachi, went Vollstandig, got Miracle amps from Adult Toshiro and Post 0 Squad Byakuya, and then evolved into a form that was so strong that even his Vollstandig form with Bankai Kenpachi's Miracle damage absorbed didn't even compare)
6.) Post 0 Squad Byakuya (Was able to scrap with the strongest version of Gerard along with Toshiro and should scale comfortably above Bankai Kenpachi)
7.) Mature Bankai Toshiro (Was able to fight the strongest version of Gerard alongside Byakuya while extremely exhausted and fatigued, embarrassed Vollstandig Gerard even with all the Miracle damage from Bankai Kenpachi absorbed)
8.) Kenpachi (While the wiki assumes it, it was never stated that Kenpachi got stronger between the TYBW and CFYOW. His growth rate that he had pre Unohana fight doesn't apply since post Unohana fight he was at his full power. Scales below Toshiro and Byakuya raw power wise since his Shikai was relative to God Size Gerard. Kenpachi goes Bankai and stomps him. But then Gerard goes Vollstandig which is >= Bankai in terms of an amp. So they should be relative in power again. And then Gerard gets Miracle amps ontop of that which would put him above Bankai Kenny. As for his body not being able to handle his own Reiatsu trying to match that version of Gerard, Byakuya and Toshiro did match and beat that Gerard, then fought a version that's incomparable to the one Kenpachi's body gave out on trying to match)
9.) Ginjo (Was stated by Tokinada to be able to defeat Full Power Res Hikone and that he had enough power to become the Soul King right then and there)
10.) Res Hikone/Ikomikodomoe (The bare minimum/weakest you can be for being a candidate for the Soul King, his feats throughout the novel speak for themselves, though they cap out at most at Shikai Kenpachi level with Soul King fragments absorbed for Ikomi. Required both Ichibei and Nimaya to seal, not even kill)
11.) Ichibei (Stronger than Yama as implied by Yhwach. Slapped base Yhwach around even though he's strong enough to hold Bankai Yama's Bankai)
12.) Yamamoto (Strong enough to passively destroy the Soul Society while actively holding back and not trying to cause any damage and compressing his Reiatsu around his body and blade.)
And these are my hot takes. Probably most controversial is Ichigo and Yhwach above Prime SK and Toshiro and Byakuya above Kenpachi. This is based on raw power/Reiatsu and not based on hax/who would win in a fight in addition to raw power. If we're talking fight then
1.) Yhwach (Stated to have the Soul King's Full Power, also has all the hax's of the Sternritter a he absorbed including the Miracle + information and powers from the souls of everyone he came into contact with during the war. Yama's Bankai. Almighty GG.)
2.) Soul King (Almighty, Compulsory, Mimihagi stagnation, the Miracle, beyond Aura level fullbring soul pull etc)
3.) Ichigo (Immune to Aizen's KS specifically but otherwise no hax but insane raw power above everyone else)
4.) Aizen (Massively more raw power than everyone below him and has had)
5.) Gerard (Can't get rid of him and he keeps getting stronger)
6.) Toshiro (Better/faster working hax than Ichibei assuming he starts as an adult, can freeze and powernull his ink)
7.) Ichibei (Name powers, controlling black, name changing hax)
8.) Yamamoto (Existence Erasing dura neg attacks, Sun armor)
9.) Byakuya (More versatility and more raw power than Kenpachi imo)
10.) Kenpachi (Spatial cutting and raw power)
11.) Ginjo (Straight up is said to be able to beat Hikone, but is mostly a beatstick without much hax)
12.) Hikone/Ikomi (Was relative to Sealed Kenpachi and was one shotted by Shikai Kenpachi even with an amp.)
I'm ready to get flamed for my takes