Monitor server logs, resource usage, etc.

A general purpose solution could work with cacti: https://cacti.net/ using RRDTool: https://oss.oetiker.ch/rrdtool/

Monitor your system with the general purpose monit program written in C.

Logs are usually accesed via systemd's journald backend or via individual log files (for example debian nginx's /var/log/nginx/…)

goaccess is a small C program that parses web server log files and produces TUI or HTML reports.

Run it with goaccess access.log -c for a TUI or with goaccess access.log -o report.html --log-format=COMBINED for a static HTML report.

See more at its website: https://goaccess.io/get-started
A detailed tutorial from Arnaud's blog at https://arnaudr.io/2020/08/10/goaccess-14-a-detailed-tutorial/