Is is something I use for a site of mine.
<VirtualHost *:443>
ServerName mytaigapage.net
ServerAlias www.mytaigapage.net
ServerAdmin webadmin@mydomain.net
ErrorLog /var/log/apache2/proxiedhosts-ssl_error.log
# Possible values include: debug, info, notice, warn, error, crit,
# alert, emerg.
LogLevel warn
CustomLog /var/log/apache2/access-ssl.log combined
## ReWrite for WebSocket
RewriteEngine On
RewriteCond %{HTTP:Upgrade} =websocket [NC]
RewriteRule /(.*) ws://servername.domainname.net:9000/$1 [P,L]
RewriteCond %{HTTP:Upgrade} !=websocket [NC]
RewriteRule /(.*) http://servername.domainname.net:9000/$1 [P,L]
# Use mod_proxy_html to rewrite URLs
SetOutputFilter proxy-html
ProxyHTMLURLMap http://servername.domainname.net:9000/ https://mytaigapage.net/
ProxyPass / http://servername.domainname.net:9000/
ProxyPassReverse / http://servername.domainname.net:9000/
RequestHeader unset Accept-Encoding
SSLEngine on
SSLProxyEngine On
# LetsEncrypt certificate
SSLCertificateFile /etc/letsencrypt/live/mytaigapage.net/fullchain.pem
SSLCertificateKeyFile /etc/letsencrypt/live/mytaigapage.net/privkey.pem
</VirtualHost>