The new error message is similar to those: Registry.toml missing - Usage / First steps - JuliaLang, and “.julia/registries/General/Registry.toml”: No such file or directory · Issue #37521 · JuliaLang/julia (github.com) .
From the information in the linked post and Github issue, deleting “/home/clement/.julia/registries/General/” may solve the problem.
After deleting the folder, try
using Pkg; Pkg.add("Suppressor"); Pkg.add("RCall");
using Suppressor; using RCall;
in julia. If everything works, then restart R and try again.