https (port 443) is designed to prevent people like you from doing things like that.
so it is correct that you are not able to make it work. and as most websites are https these days, this makes your plan fall apart.
it would be possible to do something only for http, but it is not as easy as you might think.
the chain of steps executed when a user visits a website is quite complicated and it is hard to intervene in this from within a router.
it would be possible when you use a proxy server, but I don’t think the proxy server in RouterOS is that advanced that it could do such a thing.