On (1), yes that is true to an extent - the domain discoverability is indeed mostly at the mercy of Google, and the whole "AI overview" is a garbage experience. However, looking at my own search console data (both Google and Bing), there are still quite a few folks landing on my pages through search, often for some obscure terms that I somehow documented, so it's still possible to get traffic that way. But again - the goal is less about "drive traffic ASAP" but rather point people from other networks to something you personally own.
On (2), they can, but if you use a more established provider like Buttondown or Mailchimp, and you are not actually sending spam, a lot of folks have quite a bit of success building an audience that way. I've used Buttondown (not affiliated with them in any capacity) personally before and haven't had subscribers complain about deliverability. I am planning on rebooting that this year to see how it goes. I've heard most deliverability issues arise when folks trying to roll out their own email server.
On (2), they can, but if you use a more established provider like Buttondown or Mailchimp, and you are not actually sending spam, a lot of folks have quite a bit of success building an audience that way. I've used Buttondown (not affiliated with them in any capacity) personally before and haven't had subscribers complain about deliverability. I am planning on rebooting that this year to see how it goes. I've heard most deliverability issues arise when folks trying to roll out their own email server.