Vivaldi's "Web Panels" are doing this with a lot more flexibility - you can add any site you want as a custom panel in the sidebar and resize the width to adjus

Vivaldi's "Web Panels" are doing this with a lot more flexibility - you can add any site you want as a custom panel in the sidebar and resize the width to adjust the ratio with your main window. Granted, a lot of people use it for social/messengers, but it's also super useful for resources and tools like Stackoverflow or Google Translate.