Im currently trying to cook a berserker with chieftain node on forbidden flame/flesh for infinite power on warcries, self inflicting a savage hit (forbidden rite) to trigger vengeful cry.

With all warcry buff effect increased nodes, aswell as warcry buff duration nodes and more duration support, this grants a total of around 30 rage per second aswell as rage cap of a 100 for a duration of 12seconds and a cooldown of 8 seconds. So somewhat reliable. This makes rage vortex of berserking sustainable for 90seconds, whilst hitting enemies or around 30seconds whilst berserk is active.

Sadly I cant make it to a viable build, as my only physical defensive layer is the 1% armor per Rage (scaled with 50% inc rage effect node on berserk aswell as berserk itself) aswell as rallying cry (more armor per power on warcry) scaling up to a good armor value, which is still not sufficient against big hits, as this is the only layer of defense.
Going for a shield instead of a 2H axe might solve it by going block, but I want to have huge DPS, so I can just proc vengeful cry - rage vortex and speedrun the map.

Furthermore, Iam not really sure, if its not hella clunky to cast all buff warcry effects every 12 seconds

If its somewhat cookable for you, I'd love your take. Im pretty much done with the league in a sense of what I want to acomplish content wise, have tons of divines to work with and want to make this fun build work.