Hi @christianp --
Thanks for your timely response,
and of course, foremost + especially, thanks for supporting $\LaTeX$ at all,
and thanks for having raised the max. numbers of characters (1729) to a level which enables scientific correspondence.
Could you please suggest where/how to learn (and possibly ask) more systematically about ... (focussing on my single-most-pressing remaining frustration) ... which mastodon "instance(s)" might already support all that AND "basic formatting" ??