Unhappily, I’m also using Pop!Os and I did not managed to apply the solution I’ve given and applied to my Arch system.
Mainly because there is not patched version of glibc available outside AUR.
I’ve tried to build it from the git repo of the glibc-dso version , but it was too difficult (I did not found any clear support on how to build the glibc from source on Pop!Os or Ubuntu).
We should wait the updated version of glibc (3.34+) to be published for ubuntu and derived systems
Without the patched version of glibc, the starting time for UE 4.27 on my system (Ryzen 7 3700x, 32 Go RAM, 1 To M.2 SSD) was 1 mn and 15 s on pop!Os
And , until now, I haven’t tested UE5 under linux.