I have two different generators, both portable, one a 5500 and the other 6250.I run those to power the essentials in the house plus an outlet or two and some lights. I run and extension cord from a bathroom outlet to the P61a and it runs fine on a large gauge extension cord. It won't auto light on a finer gauge cord ( too long a run). My oil fired boiler, the hot water heater ( lp gas) have digital controls and all items with digital boards that run off either generator work fine, including the stove. The generators themselves have digital voltage regulators today and in fact the 6250 has a digital control panel on it.
From what I have read is in the newer Harmans and I think mine is new enough, if the power is too dirty they sense it and just won't run. This winter we had three outages, one short. The other two were days long, the first almost 4 days the second 48 hours. I had the stove going through most of that on one generator or the other with no issues other than the manual start up when I had the skinny cord attached.. I have the house wired into a transfer switch.
Tony Ray ( forum member) does the same thing with a 7200 watt Generac but with more circuits, neither of us has had a problem and there are a few others in the forums as well who use standard modern portables with no issue. My two are one Briggs and Stratton ( the newer of the two and 6250 watts) and a Troybilt ( the older 5500 I use the most because I have the 6 circuit limit in the basement anyway and this one uses a little bit less gas, it's about 10 years old). Both run a little short of 120 volts, more like 118 but with very little fluctuation.. I run the cord into the surge protector but don't see much surge, we got some wicked spikes from the electric company actually before the power went out both of the two serious times. Enough to prompt me to shut the stove down myself and not wait for the power to go out even though it's on a surge protector. I think the power company ended up chopping the power to most of Cape Cod actually , everything was dark everywhere you looked but my house and a house here or there who had a generator LOL. Two gas stations here have back up power so I can generally get gas.
So do as you wish but I'm just here to say that a few of us in the forum run on regular modern portable generators without issue. We or I do, charge our phones, hook in the wifi, charge computers, run digital display kitchen appliances, the stove. In my case I power two refrigerators, a freezer, downstairs lights, apartment light a couple of wall outlets, one here , one in the apartment. A basement light, the boiler and hot water heater and I've never seen the 5500 go over 50%. Just hit one switch at a time and let the circuit come up to speed , hit the next etc, till all six are isolated from the street and on in the house. When the power comes back on you know it because anything not gen powered comes back on, so I just go down and flip all the switches back to street power ( they call it Line) and go out and shut down the gen.