You can easily spin up a web server (Caddy server) with a static site service the csv files generated by the BS440csv plugin. The static site here will render nice graphs using d3 for the past 30 days.
You can then access the site by surfing to your device: http://your-device-ip:5440/?p=1
(You select the person with the p parameter)
Download the correct version of the Caddy server for your platform. After unpacking the archive, copy caddy to /usr/local/bin/caddy and copy the relevant init file for your platform (eg. init/linux-systemd/caddy.service for SystemD based systems)
Copy the Caddyfile from this directory to /etc/caddy/Caddyfile.
If you would change the static site content's location, you need to update the Caddyfile. You may also want to change the http port here (now set to 5440)
If you would change the location of the BS440 files, you need to update the Caddyfile (so that it can find the csv files).
Create a directory /opt/site and copy index.html from here to that directory. You may choose to change /opt/site to a different location, but then you need to update /etc/caddy/Caddyfile.
Test manually:
/usr/local/bin/caddy -log stdout -agree=true -conf=/etc/caddy/Caddyfile -root=/var/tmp
If it doesn't complain, start/enable the service with your servicem management tools.
Eg. for systemd:
systemctl enable caddy
systemctl start caddy