- WordPress consultant hired by marketing people while "editing the theme" introduced an infinite …

Why do you give non-devs the ability to upgrade PHP plugins and edit theme syntax, shouldn't that be the site admin handling? Why are you not using staging to test? These don't seem like WP problems :/

You could have avoided all of these problems by having a developer set up a staging environment, version the site in Git and disallow file editing on the site.

Yes, WordPress gives administrators the ability to change their theme, edit theme and plugin code (which can be disabled in wp-config.php in two lines and should probably be standard if you're setting up a WordPress website for somebody), and make changes to their website — that's why their administrators. You should probably think about giving certain users like 'content people' the 'Editor' role if you don't want them doing administrator stuff like editing the theme file directly. I'd imagine most CMSs where you give your client full administrator access can cause issues with them doing things they shouldn't, like blindly upgrading plugins. Which SEO plugin gave you that 500 error? Most WordPress plugins have a 'Requires PHP' header that specifies the minimum PHP version required and refuses to install otherwise.

> - WordPress consultant hired by marketing people while "editing the theme" introduced an infinite loop which caused OOM killer. That's when we learned you can point-click your way to editing actual php code in the admin web interface! Complete and total chaos and anarchy. Fear not, you can also introduce infinite loops with a good old code editor and ship through FTP or git or whatever. Also work with different CMS and languages. Who was responsible for setting user roles on that site ? Who gave admin access to a consultant without having a conversation with ops ? If there's an op team, why isn't there a staging environment for that site ? > - Content manager "upgraded the SEO plugin" which downloaded from the Internet some hot-new code which used some language features beyond the version of php we were running, and bam, the whole thing was 500s, and everyone freaked out! Content manag…

Fwiw at a previous job we found that using blog vault backup gave us reasonable backups - a way to migrate setups (restore to new host) and workable (if a little clunky) staging environments: https://blogvault.net/ In addition: https://elementor.com/ Helped by providing a more reasonable editing experience (for a website - not "just" a blog). Both of these are paid. I think I would have preferred a managed host that provided backup and staging - but that would probably cost a little more (cash, fewer hours) - than basic php+mysql web host. Other than those two - I think we got rid of all third party plug-ins, except for a theme or two (different theme for different sites). Made wp just about manageable. Personally I still can't stand the wysiwyg "works 90% 80% of the time) editor - but then the marketing people were responsible for updates - and with wp they could do it themselves.

I found Craft CMS to be WordPress made by sensible people. Well worth the licence. You can simply disable admin changes in production, or set fine grained permissions.