Assuming those IQ7 do have "frequency-watts" function, varying power output when the line frequency varies, what you want is a battery inverter designed to control them by adjusting frequency. Some of those are hybrid (have both PV and battery inputs) and some are not.
Here's the original frequency-shift battery inverter (or rather latest model of the original series which implemented it)
The SMA Sunny Island 6048-US inverter has a maximum efficiency of 96 percent and can be used in off-grid and grid-tie battery back-up systems. 6048-US
www.altestore.com
Not inexpensive, but some are available from liquidation sales, such as this pre-wired bundle of two for $5000. I use Sunny Island in a large AC coupled system for whole-house backup.
The SMA Sunny Island 6048-US inverter has a maximum efficiency of 96 percent and can be used in off-grid and grid-tie battery back-up systems. 6048-US
www.altestore.com
A few forum members have Enphase microinverters AC coupled to a battery inverter (At least one Schneider, others Enphase Encharge)
A battery large enough to be useful is not cheap either. It is included in Encharge, but for most others you have to buy it separately. It is easily $2000 (DIY LiFePO4) to $5000 (AGM) or over $10,000 (commercially assembled lithium) for about 14 kWh of usable storage.
Larger systems would have enough surge power from battery (about 10kW) to start the motor in a central air conditioner, after which power from PV keeps it going.
A smaller system could power refrigerator, phone/internet, and the like. (Not sure there are any small, inexpensive AC coupled systems.)
For a more economical approach, what you could do is rewire PV panels from microinverters to an offgrid hybrid inverter. The PV wires shouldn't be unmated while operating. What I would do is wire in extension MC4 PV cables from the panels to a DC rated switch or breaker panel. They could be switched off, then swapped to offgrid system by unplugging and plugging in to other wires. With a typical disconnect switch, it has to be turned off before the box can be opened, which prevents you from accidentally unplugging while turned on. (Run cables to connectors inside the box.)
SQUARE D HU361RB Non Fusible Safety Switch, 30 A, NEMA 3R Rainproof, single throw 3 wire, 3 pblades
www.altestore.com
Click here for Multi-Contact Multi-Contact 8' MC4 Connector Extension #10 AWG 600V from altE® - Making Renewable Do-able since 1999.
www.altestore.com
But considering retail price of the switch (they're cheaper used on eBay, but that's the lowest I've seen retail), you would probably spend less buying a few solar panels locally (no shipping) and adding them to a hybrid inverter.