I am working on something similar in my house. I am thinking about closing off the last room with either french doors or pocket french doors.

This article has some good tips and you already have some of the elements.

https://www.stonegableblog.com/creating-rooms-flow-well-together

Where is the kitchen and doors to it? Do you have the option of using the center room of the three as your dining room?

Room divider cabinets (pony wall height) that look finished on all sides might be worth considering to help you define the different areas.

https://www.luxedecor.com/product/pulaski-ridgewood-casual-under-71-curio-cabinet-pu6705?utm_term=2693325&q=123&utm_source=google&utm_medium=cpc&utm_campaign=1341198707&product_group=300703513110&campaign=1341198707&adpos=1o2&matchtype=&adtype=pla&kw=&gclid=EAIaIQobChMIu-_SnYrs3QIViYTICh08wgCsEAQYAiABEgJeH_D_BwE