biometrics

I see this in the spec sheet:
"Supports peak shaving control in both "self-use" and "generator" mode"

Solis Hybrid Inverter 5KW S6-EH1P5K-L-PRO does support generator integration and effectively has a configurable GEN/Smart Port capability automatic generator start/stop, generator mode peak shaving, smart port functionality.
So in your earlier kettle example: 2 kW inverter generator connected to the Solis: kettle drawing 2.8–3 kW if you have PV available and/or battery …the Solis can supplement the shortfall from: battery, PV, or both simultaneously.
It behaves much closer to a Sunsynk/Deye hybrid than to a traditional off-grid inverter.
The generator does not need to carry the full kettle load alone.
The inverter can “assist” using DC-side energy.
PV production during daytime reduces generator loading automatically.
The only caveat same as with Sunsynk is that tiny inverter generators can sometimes have voltage sag, frequency drift or react slowly to sudden step loads if that happens, the Solis may disconnect from the generator input temporarily. Victron systems are still generally considered the benchmark for weak-generator handling through "Power Assist and ESS, but the newer Solis S6 hybrids are much more capable than older hybrids in this regard.
SANS compliance for the generator installation itself still needs to be considered separately. Generator output -dedicated breaker/isolator - inverter GEN input. Proper earthing conductor from generator frame to the installation earth system. Neutral-earth bonding handled in only ONE active location at a time. As soon as utility power( Eskom is interrupted) the inverter will create the earth/neutral bond on output so no need to bond the generator as GEN input is not seen as utility input to the inverter input.

The generator is nominal 1,800W so I'll set the maximum charge to 1,500W which for the 50V battery is 30A.

I'm getting a professional electrician that have experience with this type of installation, so a CoC will require a breaker I am sure.
Thanks for the feedback everyone.