Fatal Error at installation, won’t activate

I have been getting vulnerability alerts from the Health Check plugin, so I uninstalled it. The support info for it (at GitHub) said that this plugin has assumed the troubleshooting function, which was my primary reason for using the Health Check plugin in the first place. So I tried to install this one but WP gives me a red no-go, says can’t activate due to a fatal error. The Health Check plugin seems to work, but even when deactivated it trips the vulnerability scan. Perhaps not a high risk, but still not something I like to leave hanging on my site.

Doesn’t seem to be much discussion here yet, so I don’t know what to think about this failure to activate.

Thanks for any information. Would be nice if the main Health Check plugin would just be maintained properly, but that seems to be a vain hope.