Disclosure: I’m building a smaller, cheaper tool for exactly this, called Stampwork. You connect your Ghost site once, and every new post gets a branded share image with its title, set automatically as the Facebook/X card. It will be $12/month (Placid starts at $19).
It isn’t live yet. If anyone here wants it, I’ll set it up on your site for free in exchange for honest feedback. Waitlist: stampwork.sajadullah985.workers.dev — or just reply here.