You don’t need a bulk redirect for www → apex. A single redirect will work just fine.
If you plan on using www with systemeIO, you will not be able to use it in a redirect rule. Your systemeIO page currently returns 404. If you want to use it with a redirect, you can simply switch the CNAME for www to proxied and makes sure that you have your redirect rule active.
When a CNAME is set to proxied, it is published as A and AAAA records of the Cloudflare proxy. This means that you will not find a CNAME published. If you must have a CNAME, you can set the record to DNS Only, but you will lose the features and benefits provided by the Cloudflare proxy, such as redirection.
I would think having everything working as expected is more important than the colors in a test that may not be sophisticated enough to understand a user case that doesn’t align with their narrow all or nothing ideal.
I also have no idea what systemeIO is supposed to be doing. Clearly it is not serving a web page at www since that comes up 404.
The www has nothing to do with email, and if you switch it to DNS Only, it will no longer redirect.