hi henrycrum, ssh keyboard latency is a very common condition having more to do with networking than with your pine board , or with your keyboard.
... there are so many things related to keying latency using ssh including but not limited to routing, cabling, collisions, nameserver lookup, networking latency, pre-emptive multi-tasking, and a host of other things; often it never really gets debugged completely; it is annoying, and usually, there is nothing you can do about it, frankly. Its just one of those inherent natures of the beast using ssh...
marcushh777
please join us for a chat @ irc.pine64.xyz:6667 or ssl irc.pine64.xyz:6697
( I regret that I am not able to respond to personal messages; let's meet on irc! )