Thanks. After creating this post, I discovered a similar one (had already searched, but...), so rather than be redundant, my further thoughts, findings and suggestions are here. I realize there are all kinds of hosting variations, but surely there is some common guidance for manual renewal.... if only "there is no manual renewal process. Just install the same certificate using the same method you used to create it." (That might be incorrect, but I hope you get my point.)
As for GoDaddy's cPanel and CertBot, GoDaddy explicitly says they don't support it. The above thread has a link to the procedure I will follow.