Provide an RSS feed. The only thing that'll stop people following that is Google Safe Browsing. You'll still need to provide all the other methods for letting people follow you, but if you advertise your RSS feed, people might start using it.

(If you're feeling technical, you could set up an ActivityPub bridge, to let people follow you from social media too. If you're using Wordpress: https://wordpress.org/plugins/activitypub/)