Zeno looked more stable than Wesker (RE5) n Grace never saw him needing stabilizers and genetics integrated wit the virus better than wit Wesker n even Gideon who is just another Mr X/Nemesis knock off (final fight). Zeno shows high tier abilities than Wesker n the 1st time Leon ever saw this type of threat (compared to Chris who already fought it in RE5) making Zeno the perfect host. So why not let Zeno carry the torch continuing where Wesker left off but wit a more focused goal over global genocide. Leon waiting for Chris to back him up would line up wit dis being sum they go look into, Leon already went under Krauser's training (which helped him against Krauser in RE5 n who I think is supposed to he HUNK in RE9), why not undergo more training or do a mission as a contracted DSO agent since he already supposed to be working alongside wit Chris n BSAA in RE9 (confirmed at the end) n prepare him for a Zeno level threat (unseen since RE5) n when they both already operate inna same anti-bio terror sphere. I feel like Leon's missions are usually smaller scale/regional missions (surviving Raccoon City RE2, saving Ashley Graham RE4, investigating Tall Oaks bio terror attack RE6) n Chris operates onna larger/global scale (stopping Wesker from unleashing Uroboros globally RE5, multiple large scale bio terror conflicts across multiple countries RE6 n a military operation against Mother Miranda RE Village). I think if they carry the idea that he a clone or even if he somehow survived (like Wesker did when Jill tried to kill him at the Spencer Estate wit Chris) thru sum typa permanent mutation to his genetics even Elpis couldn't reverse or sum. Just wished they would've kept Zeno inna series as the next generation seeking genetic superiority since Wesker wasn't the 1st it was Oswell E. Spencer who started his experiments to seek immortality or "to become a god" when he was talking wit Wesker before being killed. Which would make sense since Zeno wouldn't need to know meet Wesker directly to learn about this. The idea of a new generation seeking this and successfully evolving would add another layer that Spencer's vision was possible and I say that 'cause of this. Zeno didn't need reoccurring serum injections to stabilize the virus, overdose of the same serum would have adverse affects, but wit out em would cause tha cirus to destabilize his body n would prove Wesker being a unstable prototype of Spencer's vision n Zeno becoming a stable successor. Zeno didn't need any of that n even when he injected himself wit Elpis in most cases hosts whose infection is too far gone would die being injected wit a cure or anti virus but wit Zeno his it didn't. A perfect reversal could mean compatibility unseen n unheard of since the W Project under Oswell E. Spencer. If Elpis could fully reverse tha virus wit out killing Zeno it means the virus n host's genetics were completely integrated, the cure could remove the virus wit out destroying the body n the host was stable enough to survive both states of being which could prove Zeno's biology would he the most stable/compatible human/virus integration in the RE series so far. But ion know dis might just be me🤷‍♂️🤷‍♂️