I have been using Notepad2 on Windows XP for a long time now.
I used Komodo Edit for ever but can't get it to
run or compile on Apple silicon or some tries at VM.
Found Geany on Raspberry Pi and also on Homebrew for
macOS. Geany is awesome. The sidebar symbol tab that
navigates code by clicking sub names is paradise. The
"Overview" plugin adds adds that extra dimension to
navigation. Geany wants to be configured for maximum
effect:
Edit > Settings
View > Change Color Scheme
Tools > Plugin Manager
Some fun plugins:
Addons
Export
File Browser
HTML Characters
Line Operations
Lipsum
Mini Script
Overview
Save Actions
Split Window
Tableconvert
TreeBrowser
Kudos on attempting to write your own editor with real
time syntax highlighting! What I miss about Komodo is the
real time bug detection for Perl, that was crazy. But it
still runs on Intel...