I have never won a 4 vs 1. While having played a lot SW games I have only been pushed into such situations two or three times that I recall, but not won them. I have none-the-less won several 3 vs. 1s, and many, many 2 vs. 1s.
I tend to play on Scare starting with the builder kit, ignoring my starting island. This lets you get to and punch into the pumpkin within the first 30 seconds. You can then sack all 16 (8×2) chests almost always before anyone else gets there. A couple of lvl 1 sharpness swords + an anvil and you are almost always stronger than any other single player. Stay there, continuously enchanting and upgrading with the anvil, getting more and more over-powered as the round progresses. With enchanting exhausted one can go on the offensive. By then a 3 vs. 1 becomes only a medium difficulty challenge, not impossible at all. I always get (falsely) called a "hacker" when I win though. Only a few players understand anvils, I've noticed o_O
Related on Scare, I have won one or two 3 vs. 1 and several 2 vs. 1 battles with OP chests in a more amusing way. Start the same, collect all gapples from the 16 chests, then go to the bottom level. Then race around the edges when others come down and knock out the clay floor beneath them with the 1337 pickaxe. A lot of fun.