In reply to cinza.

On the topic of media/images, they are already responsive. At least that has been my experience. Have you hit a specific issue? Or, is there an enhancement that you'd like to see? If so, have you opened a ticket or does one already exist?

Container-type blocks are also responsive out of the box. However, the are not as flexible as they could be, and I know there are some open tickets to enhance the tools around those. Wide adoption of CSS container queries from all browsers would certainly help with this too. Again, it helps to talk about specifics, the varying methods used to accomplish those specific things, and what the best direction for core is. There is no shortage of discussion around this.

As for which feature should garner the most focus, everyone has a different opinion on that. But, in general, I wouldn't put some features on hold because others are still in-progress.