Learn Routing /VoIP

I want to learn routing/VoIP. I’m CCNA with couple of years experience want to understand routing for HUB/Branch office deployments on practical level used in offices. Mostly at datacenter level want to learn in deep of how it works. What is best place to start learning about it. Should I learn design also to get complete overview or just stick to routing. I’m looking for books,videos or GNS3 setup or anything. I’m looking for more of practical approach along with best books to understand. And similar with VoIP or Phone system side too. I have zero idea about VoIP side. I want to learn basics like CCNA Collaboration(they don’t have it right now) or something similar to understand which codecs and why this qos is like this and make sure they are good at business policy level.

I currently work with VMWare SD-WAN, Aruba branch switches, Meraki for Switches,APs(Indoor/Outdoor), Fortinets for guest wifi and IoT policies.

I’m aware of Cbt nuggets, INE, BOSON, Fortinet training. I used cbt nuggets before. I read wendell odom (CCNA) before. I’m looking for next step from there to become Sr.Network Engineer do CCNP or further. But foremost at first looking for routing side to understand and troubleshoot at enterprise level.

Thanks in advance 😁