I was going to say that the difference is that what you're describing with Powerwall is only an 'on-off' control of the solar. However then I remembered that Enphase IQ micro-inverters do have the capability to throttle power with frequency shifting. That is documented here: https://enphase.com/sites/default/files/downloads/support/Design-Considerations-AC-Coupling-Micros-Battery.pdfAs far as I know, the gateway supplied with the PW (I don't see a brand on it but I think it's a Tesla manufacture) does the same thing regarding shifting the Hz of the PV array up to lower output if (a) the battery is charged and (b) there's more solar available than needed. My computer's UPS monitors powerline Hz and it's easy to see the shift upwards to 61-62 Hz around 1:30pm when when the battery is charged and the sun is out. PV output will lower and raise (if available) to meet just the house demand. Around sunset, when there's no PV juice available, the Hz settles back to 60 as the battery takes over.
However this solution won't work too well for our OP if he wants to run DC from the array to mitigate serious voltage drop considerations.
The (legacy?) SMA feature is also full range 0-100% throttling of PV inverter output based on the battery inverter adjusting the frequency between 60Hz and 50Hz. (Note that there isn't an standard here, and these features aren't enabled by default on interactive solar inverters; one had better make sure that AC coupled equipment is all programmed appropriately to create compatibility.)
(BTW with Powerwall it is the battery units themselves that shift the frequency (it has to happen at the source), although I would wager there is some necessary communication required with the gateway involved as well. The gateway you have is Tesla manufactured and works only with Powerwall.)