@alex
Okay so the solution is multiple clients.
Before Akkoma-FE (a web frontend I have installed) had post-editing or even “delete and redraw”, I used FediText (then called “MetaText”) to do that. I only opened it for that! Then went back to Akkoma-FE. These days FediText is not good for that because it loses the markdown formatting but Akkoma-FE is good for it now so now it’s the only thing I open it for. (And in both cases I have to be quick since I have app limits on.)
I make most of my posts in Emacs. Including this one; I have a shortcut set up that lets me long press your post in the RSS reader which lets me type the reply in Emacs.
And same when I want to post a link, I have a shortcut to use on URLs that opens Emacs to type the description (and the tags for link hut).
Or when I just want to make a text post of my own, that’s Emacs. It even lets me select some text from another post and hit a button and that gets posted. (This is all in addition to the excerpts that automatically get posted when I make blog posts. Yeah, yeah, I’m an insufferable firehose on ActivityPub, I understand that. I worry about that a lot but I haven’t figured out an answer yet.)
But then for quick replies to mentions and DMs, I use a Delta Chat plugin for that. The mentions become Delta Chat emails and I can reply right away. (If I want to use Emacs or markdown in the reply I can still switch to Emacs manually.)
I still use FediText for one thing: posting images and sound that originate on iPad (like screenshot from manga) since unlike Akkoma-FE it works from the share sheet, and FediText has a much more comfy space for writing and editing description text. Art that I have on my headless Debian machine (that runs all this Emacs and blog-posting and bookmarking stuff), I can post directly from there with Emacs to write those descriptions and GIMP #ChangeTheName to crop out thumbnails for my /gallery.
So Akkoma-FE has an app limit (of like 25 minutes and it also eats up of the 60 minute Safari app limit), FediText has an app limit of I don’t remember how much because I try to only use it for media posting, the RSS reader has a limit that’s lifted on Socials Saturdays which is where I can catch up with all of y’all♥︎, but Emacs and Delta Chat have no limits which is how I can post and reply to mentions all week long. A li’l solipsistic perhaps but I figured that replying to a question directed to me specifically was more urgent than engaging with what people send out more undirectedly to the wider world. (And even then I’m not on my Delta Chat 24/7. It’s fenced-off, too: I can only use it at home and notifications are off during the night and morning.)
All this a l’il self-indulgent way to say: use multiple clients! Each has its own strength.