Pronunciation of "не" in negative sentences

Hi!

Does the pronunciation of "не" change depending on whether a consonant or vowel is used?

Работа его уже не интересует.
Она с ним давно не разговаривает.

I often hear two variants of pronunciation of words with an E letter. Either "je" or "i".

-> не интересует. I hear either нi интiрiсуjет or нjе интiрiсует.
-> не разговаривает. I hear either нi разговариваjет or нjе разговариваjет.

Are both versions used for the negative "не"?

No. It just depends on how quick and fluent are you talking.
In first case and fluent speech you have two sounds of 'i' one after another. It becomes something like long 'ee' with raise of tone in the middle. I think everyone who will try to speak quickly will end with this pronunciation.

IPA:
[nʲɪːnʲtʲɪrʲɪˈsuɪt]
[nʲɪrəzɡɐˈvarʲɪvəɪt]