How do you pronounce /ɪə/ in modern RP?

I wonder how to pronounce /ɪə/ in modern RP.

When I hear audios of words like 'here', 'near', 'beard' in dictionaries, I hear something like 'ɪje':

• https://www.oxfordlearnersdictionaries.com/definition/english/here
• https://www.oed.com/dictionary/here_adv?tab=factsheet#1752236
• https://dictionary.cambridge.org/pronunciation/english/here

But when I hears audios of the word 'zero', 'cereal', 'series' I hear something like 'ɪː'

• https://www.oxfordlearnersdictionaries.com/definition/english/zero
• https://www.oed.com/dictionary/zero_n?tab=pronunciation
• https://dictionary.cambridge.org/pronunciation/english/zero

Am I hearing wrong? If so, what do those speakers say? If not, how do I know when to pronounce /ɪə/ as ɪje and when as ɪː?

The actual sound of the vowel in such words will vary from speaker to speaker and from time to time. When speaking slowly and carefully, the vowels will be different from when speaking quickly.

I do note a diphthong in "zero", but the second part of the diphthong tends to blur into the "r" sound. Compare the sound in "Zero" with "Here is". And compare how "Here is" is pronounced, compared to saying "here". The sound in "here is" is very similar to the diphthong in "zero".

When "Here" is spoken slowly and carefully, you can approximate with two syllables. "Hee-uh". When spoken faster, the sound blends more.

I don't hear much difference between the sound in "zero" and in "beard", except that the following syllable tends to overshadow the first.

This kind of variation in vowel is pretty common, and doesn't affect understanding. If you say "zee-uh-ro", you'll be understood. Note that the "r" in "here" should be proununced, unless followed by a word starting with a vowel