Uuuhyea that’s weird because I can’t find which CNAME records it’s talking about which is apparently “conflicting” …
So yea, you can still try to delete the www A record … Its only use is that if you go to www.yourdomain.tld, you should end up on your server (tho in fact you need to add the www.yourdomain.tld in yunohost’s domains, even tho you already have yourdomain.tld configured …)