Keyboard & Keyboard viewer not working properly

Hi,

I've experienced problems for the past few months:

1. keyboard viewer:

I always keep showing keyboard viewer & the accessibility keyboard enabled (minimized). But when the screen is locked, the keyboard viewer disappeared. When I logged in again, I checked the settings which shows that the keyboard viewer and accessibility keyboard should be showing, but they don't. What's going on?

2. Keyboard:

(a) Chinese input problem: When I do Chinese typing (Canjie - traditional Chinese), it sometimes turns into a combination of English characters and strange Chinese characters.

e.g.I type "今"(In Chinese input: o i n spacebar--spacebar acts as enter), it turns out showing "伐n" where "伐" in Chinese input is "o i".

Then I have to switch back to English input and to Chinese input again. This seems to be a quick fix. Sometimes that don't fix, then I have to type slowly.

It is extremely annoying.

(b) Capitalization in strange positions: When I type in English, sometimes a word will be capitalized randomly. I have already disabled most of the keyboard shortcuts.

I experienced the same problems both in Mac Mini (M1) and MacBook Pro (2012). [I paired the Mac Mini with a Logitec K580 keyboard]

My old MacBook worked perfectly fine until recent updates, maybe several months or a year or so.