Yes, my inverter produces a "perfect" sine wave. But that's because I spent extra on the inverter for other reasons. I wanted an inverter powerful enough to give me 9 kW conversion from DC to AC, and also have powerful charge controllers. Basically, there was no use spending a lot on solar panels to give me up to 10 kW coming in unless I made sure that power could be put to somewhere useful. (One weak link in the system makes the overall throughput weak and horribly inefficient.)
As far as waiting for a 100% free charged EV goes, it's not about improvement in EV technology that I'd be waiting on. It'd be about upgrading my current solar system. The system I had put onto my house was meant to provide as much as my house usually needs and not much more -- why pay for more than I need? I overdid it a little and there are many days I have a little extra power that could be used to charge an EV. Especially if I use an optional feature of my inverter to power a separate circuit panel intermittently -- only if my home batteries are at a configured charge (say 80% or more). The idea being that if I have enough battery charge to make it through the night (probably) before the sun comes up the next day, then use any power above that for stuff I don't need all the time.
Imagine me coming home with an EV, which means it's time to plug it in to charge it like all other EV owners do every time they come home. And imagine I had two charging outlets to choose from: either a 240V/48A constant powered outlet to charge the F-150 Lightning for 19 miles for every hour it's charged, or a 240V/32A outlet that's powered only some of the time (giving 14 miles for every hour its charged). If I came home with a low "tank" in my EV or if I planned to do a lot of driving the next day, I'd plug it into the constant powered outlet knowing that most or all of that power would come from the grid. (If I need it charged I need it charged, no getting around it.) But if I come home with a lot "left in the tank" I'd plug it into the intermittently powered outlet. I may get a charge for a while until my home solar batteries drop to 80% charged (because of power demand from charging the EV plus demand from the house) and at that point it'll automatically shut off without me having to monitor it and go out to the garage to unplug the EV. The same with it automatically start charging the next day if I leave it charged after the sun comes out and my home batteries are charged enough. Then there's also the DC to AC conversion max of 9 kW (the intermittent charging of 240V/32A is 7.7 kW, so for it to be powered not only do I need a high home battery charge but also not be consuming more than 1.3 kW with the rest of the house).
Mostly for monitoring so that you know how much your home consumes vs how much is directly available vs how much is in the battery subsystem accounting for inefficiencies, etc. and tells you realtime how many minutes, hours, etc. your system can provide power. I would also display how much energy is generated versus stored, time of day, etc.
That way you could play around with which devices are plugged or turned on when you lose power. Also, many gadgets still consume power even though they are “turned off.” It can be a significant amount of power. That probably means getting power strips for those devices — the good ol’ mechanical power switch.
With computations and knowing how much power you consume would be useful. Then you could better control the overall consumption.
Also, I have not tested this out (a disclaimer) but many devices that use AC and have a bridge front end and switcher back end will run off of DC. Example: your desktop PC. Obviously, AC motors or devices with an AC transformer won't work. Details to be worked out because the DC voltage has to be high enough for the switcher to turn on.