Full gear was around 30kg and very well balanced over their body. Ever wore full medieval plate with all the extra's? You'd know it doesnt even feel as heavy.
For the people who think knights had trouble moving and were slow:
https://www.youtube.com/watch?v=q-bnM5SuQkI
https://www.youtube.com/watch?v=5hlIUrd7d1Q&t=5s
https://www.youtube.com/watch?v=qzTwBQniLSc&t=32s
And FYI, only the lawbringer has full plate in this game. The other 3 have very light gear. The warden seems to wear a few pieces of plate, some chainmail and a gamberson. This would actually make his gear lighter than what the Orochi and Kensei have in this game. They wear wooden armor (which is dumb), but it's safe to say it's hardwood otherwise there is no point in wearing it to begin with. Hardwood is very heavy.
EDIT: As a reply to you, you never worse plate without the rest, it would be really uncomfortable and pretty useless.