@choyer If you prefer a pure-Mastodon UI/UX then there is c.im with a 5000-character limit.
There is also c.wtf with the same limit but is running on #Rebased, a fork of #Pleroma.
Or, you can use #WriteFreely or #Plume, fediverse software designed for long form writing.
There are also #Hubzilla #Streams and #Socialhome with unlimited characters.
Those are what I can remember, I'm sure I've forgotten one or two.
I hope you find your new home for long writeups!