The reason the Telegram ask got you banned is the same reason a raw FB group link or a direct email ask will: Reddit kills overt off-platform funneling in posts and comments. So stop putting the call to action in the post. For a content sub like yours, the funnel that actually works is your profile. Put the Telegram or FB link in your profile bio and social links, maybe a pinned post on your profile, and let the photos do the pulling. People who want more click your name and find the link themselves, which Reddit tolerates far more than a link in the post.
For emails specifically, you can't really collect them on Reddit directly, so send that profile traffic to a simple landing page or a link-in-bio page where you capture the email or list your FB group and Telegram. Keep growing the sub with consistent posting and reply to the people who upvote and comment, they're the highest-intent audience you have. The one hard rule after your ban: never a raw join my X in a post, the link lives in the profile and the content is what makes people go look. Slower, but it doesn't get the account nuked.
Best,
Floqal