I am using a Pixel 6 with 128 GB. At the moment settings says:
system: 13 GB
audio: 15 GB (my favorite music bands)
apps: 14 GB
all the rest: ~ 550 MB
So, I am far away from 128 GB. But that's because I do move regularly my pics and videos to my desktop computer and I am not a heavy user. I know people, who store their years old pics and videos just on the smartphone and have about one hundred apps on it. With this behaviour you will reach on every device (which has no extra sd card slot like the pixels, but even then ;) ) the limit sooner or later.