I tried also recently the beta version of Julia 1.6 and the speed improvement of installing/loading package are quite impressive. Essentially, packages get precompiled after installation using multiple threads.

Beside this, if you only infrequently install/update package, you can use PackageCompiler.jl. I use it for PyPlot.jl (based on matplotlib), DataFrames.jl, ... and plotting some data quasi instantaneous as it is in python (even the very first time in a session).