This is probably the issue. Galaxy works best under Python 3.5 – and there were some prior issues with 3.6.
Could you try 1) removing both environments, 2) creating a new virtualenv .venv under /galaxy, then 3) executing sh run.sh.
You may be able to – or need to – skip step 2.
Related Q&A that still applies. It is the most basic way to start up that tends to work for most. The most current Galaxy release is 20.05, so swap that in. The rest is the same.