Thank you for your reply, and for giving me some encouragement, agray!
Despite trying it’s not working, however.  I have something like you suggest in my nginx config, which I’ll post here:
` # This file overrides default nginx HTTP settings for my.example.com 20
Mount this file as “/var/lib/nginx-conf/my.example.com.conf.erb”
map $http_upgrade $connection_upgrade {
default upgrade;
‘’ close;
}
server {
    listen 443 ssl http2;
    server_name subdomain.example.local;
    keepalive_timeout 5;

    location / {
        proxy_pass http://127.0.0.1:8501/;
    }
    location ^~ /static {
        proxy_pass http://127.0.0.1:8501/static/;
    }
    location ^~ /healthz {
        proxy_pass http://127.0.0.1:8501/healthz;
    }

    location ^~ /vendor {
        proxy_pass http://127.0.0.1:8501/vendor;
    }
    location /stream { # most important config

        proxy_pass http://127.0.0.1:8501/stream;
        proxy_http_version 1.1;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $host;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;
        proxy_read_timeout 86400;
    }
 }`

Also I have that on starting up streamlit emits:
subdomain_1     |   You can now view your Streamlit app in your browser. subdomain_1     |  subdomain_1     |   Network URL: http://172.21.0.2:8501 subdomain_1     |   External URL: http://79.247.21.93:8501 
So I switched all the 172.0.0.1 to 172.21.0.2 , but unfortunately it did not work either …