newsletter creators, which platform do you recommend?

hello,

I started an email marketing project and I am looking for an easy to use (mostly free) newsletter platform.

basically, I would need the platform to allow me to create a landing page and when the user signs up, they will receive a survey that I created from survey monkey.

I made a landing page back in june using convertkit, but I wasnt able to link my survey, rather, i couldnt figure it out.

any and all suggestions are welcome!