Please avoid trying to scoot around the character limit by posting images with text on it, especially if they don't have #AltText. They are inaccessible and generally a bad experience.
Please use #Fediverse software that is made for long posts if you want to write long posts.
Long multi-part threads on #Mastodon are okay, but if they're really long, I would advise you to put a post counter in each post, like this:
(2/2)