I want to use the key combination Option + 2 + 4. However, currently I only see "Send keyboard shortcut" only using the combination Option and 1 other button. I tried using Opt key Down then 2, then 4 then Opt key Up but it still doesn't work.
macOS doesn't support multi key shortcuts, so this really depends on how the app you are trying this with interprets the input. In general the approach you tried in your first post looks promising, but only if the app that you use this with would also "read" it like we do