What is a symbolic Beast?
“Thus he said, The fourth beast shall be the fourth kingdom upon earth, which shall be diverse from all kingdoms, and shall devour the whole earth, and shall tread it down, and break it in pieces.” Dan 7:23
Answer: fourth Beast = fourth Kingdom. A beast simply means a kingdom, which is a nation, or a power.
Example, “And I stood upon the sand of the sea, and saw a beast rise up out of the sea, having seven heads and ten horns, and upon his horns ten crowns, and upon his heads the name of blasphemy.” Rev 13:1
In other words, Daniel sees a kingdom or Nation coming out of the sea (densely populated area).
See What does the “sea” present in symbolic prophecy?