Maybe pointing out the obvious, but if you book with a real "old fashioned" travel agent (i.e. travel agent with personal access to a GDS, not an OTA/call center...), they would be able to make any changes and handle any requests in real time without having to wait for a response that will never come from El Al's call center/WhatsApp/Messenger...
The only question is what fee they would charge on top of the ticket.