These things are so subjective, so each person's opinion is completely valid (for them)...
I have never used a universal fit that sounded as good, offered the protection of, and the CONSISTENCY of a custom mold IEM. That includes Shure, Carvin, Sennheiser, Westone, KZ, and several of the other available on Amazon types.
My first set of CIEMs were made by Alien Ear. Terrible customer service, but the 3 driver IEMs I bought were great until the shell cracked/broke after 8 years of heavy use.
Since then, I've moved on to Ultimate Ears - first dual driver (UE5) and now 3 driver (UE7). Paired with either a Shure PSM300 or an Xvive system (backup & "throw & go" situations), as long as I have control of my mix (and time to dial & eq), I know I'll be happy.
(FYI, control & time are facilitated by owning the IEM mixer - X32 - and taking time to dial in the band & eq as a necessary preparatory step during rehearsals, soundchecks, etc. Once I got familiar with the process, making small adjustments at a gig became quick & simple.)