What I would like: Infinite tabs, they don’t get too small in the tab bar, newer ones to the right, older ones can be accessed by scrolling left. Older than last 15 don’t take up memory. Tabs get saved into disk/cloud and reappear when you restart the browser like on iOS. Basically so you can put off dealing with your open tabs indefinitely.
Open tabs are synced between devices via iCloud. In the tab icon view you can see tabs open on other devices listed. You can click to open one or ⌘ + Click to open them in new background tabs.