@Alessandro_Kornowski , I’m a little confused about your post, but are you asking if you can connect multiple phases from the generator to the single-phase input on the Deye inverter? If so, then the answer is no.
I connected my BYD Atto-3 to my Victron off-grid system, but I had to make some adjustments to the inverter settings. The V2L output is a “protected” supply, meaning it has an RCD (safety switch) and cannot be directly connected to an inverter that is connected to a switchboard with protected circuits (RCDs). Fortunately, the Victron Multiplus inverter I used has a unique earth (ground relay) setting, which enabled me to use a “protected” supply from the Atto 3 without any issues. I do not know if the Deye 8K hybrid inverter has this same feature, but the Deye inverter does have dual AC inputs, so I believe the generator AC input might work with V2L.