I was one of the luckier ones to be in a party but even at over 23K, 2,000CR more than recommended amount, I tried what people were complaining about. Basically, that solo, unless you are a whale with maxed gear, doing Gauntlet solo is not feasible. Here is the official difficulty range and it does seem to not be exactly what the requirements description suggests below…
“The difficulty of Helliquary bosses will be dynamically set based on the number of players, corresponding to the lowest and highest possible difficulty”.
The statement " ‘based on the number of players’ is very GREY. Theoretically, going in with one should be easier than with 8 to kill but that is totally inaccurate with 130M HP. We all pretty much know that unless you go in with four players over 21K nobody will have a chance of beating the bosses.
I do not think it is anything other than by design, but theoretically, doing a Gauntlet solo when nobody else is on the server should not be at the same difficulty for eight players. Just saying…