Who owns B- registration? China or Taiwan?
From your second link:

Aircraft registered in the People’s Republic of China traditionally
have had &quot;B-&quot; followed by four digits.
B-0000 to B-9999

Since 2018, the following registration schemes are also in use:
B-000A to B-999Z (General)
B-00A0 to B-99Z9 (General)
B-00AA to B-99ZZ (General)


And for Taiwan:

B-00000 to B-99999 after 1990s

so there won't be any confusion, one has 4 digits/characters after the dash, the other 5 digits.