Interactions with Mastodon and the Fediverse

OK, so with cross-posting to Mastodon set-up, the default is to cross-post even when the option is hidden, ie you have to reveal and untick the option. Also, need to consider (i) whether I need to have a general blog in addition to the history ones, (ii) whether the general one becomes my Fediverse account and I drop Mastodon per se. I have no particular interest in federating beyond there but at what level do I have a choice if I don’t run my own instance (I currently have Threads blocked and would likely do the same with BlueSky). Questions, questions…