A simple key remapping solution. Copy to ~/Library/LaunchAgents/ - Possible values are listed here: https://developer.apple.com/library/archive/technotes/tn2450/_index.html.

local.RemapRightOptionToDeleteForward.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>local.RemapRightOptionToDeleteForward</string>
    <key>ProgramArguments</key>
    <array>
        <string>/usr/bin/hidutil</string>
        <string>property</string>
        <string>--set</string>
        <string>{"UserKeyMapping":[{"HIDKeyboardModifierMappingSrc":0x7000000E6,"HIDKeyboardModifierMappingDst":0x70000004C}]}</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
</dict>
</plist>

hat tip to tommit