Add new Cypher and or ability to prefer or negociate

My suggestion is maybe ridiculous, but the idea is to add the ability for two hosts to negotiate the cypher based on the cpu capabilities or admin preference.
Chacha20 would be nice to add, it seems to be faster then Salsa20 and gives a bit more performance on slower cpus even if zerotier implements aes not every cpu has aes-ni., like the Edgerouter-X, intel atom and some smartphones.

I agree, and I think zt agrees as well to some degree. They posted an article a few years back that AES is coming in zt v2. To get FIPS capable as well as take advantage of hardware accelerated encryption.

I can’t say I really care if most of these other types are supported myself, but AES-NI acceleration would be pretty welcome. Not just for raw performance/throughput, but to free up CPU. AES-NI might actually be slower than a modern high performance CPU but it would free up CPU cycles for other tasks if the performance demands fit in the AES-NI chip.

https://www.zerotier.com/2019/08/21/zerotier-2-0-cryptography-notes/