Just adding another data point. I'm doing a similar installation, using a 24kw Generac whole house unit. It has instructions to do the N-G bond at the generator (if needed), but does not come that way from the factory. I believe they recommend N-G bonding at the transfer switch.
Yeah great advice. Just to add though, if you are off grid and don't require an auto transfer switch pre-inverter, then you could just put a little mini single 2-pole breaker panel there instead, dedicated for the generator circuit, where the N-G bond (for running in inverter bypass) could be made (as long as there is no N-G bond in the generator itself).
Then when the inverter is running, theoretically its own internal ATS circuit should be disconnecting from the AC input's neutral, so it wouldn't see that N-G bond coming from the input side (provided by the mini breaker panel), for whenever it was being the active unit making the N-G bond.
Of course, whether your running with N-G bond at generator, or having it made in a pre-inverter panel or an ATS, I would recommend at any rate to check on my specific inverter (in bypass, and while running on inverter) to make sure how it is handling the AC input neutral (in both operating modes), before I rolled out any production solution.
If the AC input of the inverter was still keeping the AC input neutral connected while inverting, one might need a relay on the input neutral to make the neutral go open from the AC input (anytime the inverter is turned on), so as not to have two N-G bonds at same time.
Or one could even have a 3-pole breaker with a neutral in the generator mini-panel, and manually shut it off when the inverter is running, to ensure that N-G bond is broken (the one going into the inverter AC input) while the inverter is inverting and it's providing the N-G bond.
You could also use an ATS instead of a mini-panel, set up using only the generator input (with other input empty), and when the generator turns off, the ATS relay turns back to NC side, would just be hooked to nothing, which would break the N-G bond being provided.
But my suspicion is that most inverters which have a built-in ATS, are going to disconnect neutral on their AC input (while inverting), since it is assumed that they are always being provided power via a native N-G bond upstream from that input, as many normal grid installations would have that attached to the AC grid input that is always live (when not off-grid)...