Three simple text-based steganography ideas:

1. Substituting aeiocx letters with their Cyrillic counterparts if the cover text is Latin-based, and vice versa. Implemented a long time ago in one of my scripts.

2. Encoding message bits in word lengths: 0 if even, 1 if odd. Can be based on simple Markov chains but may need some AI assistance if the cover text is not required to be gibberish.

3. Hashtag-based encoding: e.g. 4 predefined lengths can encode two bits. The message can be encoded in alphabetically sorted hashtags and then they can be shuffled. Also, the word pool can be fully pre-picked manually to match your post topic.