Your gmail notification point doesn't track, but its the most minimal point so i'll drop it.
I dont think Substack is specially just a Nazi platform. I think they are Capitalists that will use any kind of speech to make money. While bootstrapping, they found a niche in leftist independent journalism. Now, they view far right hate as profitable, both directly with Nazi commentors and being paid large sums to enshittify the platform from far right figures.
They dont care about racism or hate because they are rich and it makes them money. That does make them bad people, no matter how many leftists they also profit from.
I absolutely expect they will follow a Twitter style path from here on out, with or without Musk at the helm. Once you let the Nazi's into the bar, they take over by driving everyone else out. Substack has said "come on in!" so they will. Some leftist will remain for a while, but eventually the Nazis will be all that's left.
I expect you make some kind of living off Substack? Maybe look into Ghost as an option. They take way, way less money even when fully hosted.
Stamers conditions are more complicated than that. Most are in the article i linked. Hes demanding a two state solution and a lot of concessions from Israel when they are likely to meet none of them.
The UK has basically committed to recognizing Palenstine as a state.