how to design a scalable and reliable notification systemtho it's tough

im workin on a system that needs to send notifs to users via multiple channels like email sms and push notifs. we want to make sure messages get delivered reliably and the system can handle a ton of outgoing messages. were thinkin about usin a message queue to separate the notif sender from the channel specific delivery agents but im curious about best practices for designin this kind of system. what have you guys seen with buildin scalable notif services any advice on queue selection retry stuff or handlin delivery failures