Folders, ssh, key auth, sftp and scp are the main things I’m looking for.

suggesting that anyone who wants a central console for their remote systems must be somehow incompetent

IMHO that's exactly what ~/.ssh/config using its Include directive as shown in https://lemmy.ml/post/29858248/18510482

       Include
               Include the specified configuration file(s).  Multiple
               pathnames may be specified and each pathname may contain
               glob(7) wildcards, tokens as described in the “TOKENS”
               section, environment variables as described in the
               “ENVIRONMENT VARIABLES” section and, for user
               configurations, shell-like ‘~’ references to user home
               directories.  Wildcards will be expanded and processed in
               lexical order.  Files without absolute paths are assumed
               to be in ~/.ssh if included in a user configuration file
               or /etc/ssh if included from the system configuration
               file.  Include directive may appear inside a Match or Host
               block to perform conditional inclusion.

from https://man7.org/linux/man-pages/man5/ssh_config.5.html

So what I think people are highlighting is not that your need is wrong, rather that you rather than going back to fundamentals (e.g. lower command-line or even configuration here level stuff) you are looking for more complex and specialize tools. That tends to be reasonable in the Windows world where people are often looking for GUI but in Linux, started from Unix and thus CLI, this is a process that will often lead to disappointment. I believe people who are saying things perceived negatively here are pointing out, maybe poorly, a cultural difference that will be problematic in the future, thus why they are insisting.

I've been using Linux for almost 30 years, and I agree with you completely. There should be a plethora of tools to organize SSH hosts, but unfortunately none of them are great, or at least I've never particular gelled with any. I just remember the hostnames and what user I happen to use for each, and copy my keys around, because I jump around between a lot of computers.

I did use SSHwifty for a while because then I could just jump into a browser and go to a webpage with all of them. Dunno why I got away from that, it was handy.