Be aware that RSI is a real risk and once you have it, it never goes away. That is serious, even critical, if your job is at the keyboard. So be moderate.
I’d say time spent typing is much less of a factor than how that typing is done.
(*) The first big fix for me was switching from a desk to laptop on a couch where I could change positions every few minutes. The short travel and light weight of laptop keys also helped. I switched back to a desk more recently, but I kept the low-profile light keys, and the general awareness of postural stress.