I can't understand exactly what your question. do you remeber what situation there is in K-drama? When you ask some one who are younger than you or similar about something, you can use this " ~하니?" = ~ ne? also you can use this "~하디?" = ~ de? but to use " ~ de? " would be kind of the vernacular.....

I know what you mean, I've heard it like that too. I heard some people say it's because your tongue is in the same position when you say 네 and 데 so those sounds are similar, and same for 미 and 비 if you try it out yourself. You should remember than 네 does not 100% equal 'ne', that's just a close English representation of the sound to make it easier for English speakers to learn it. But it is not an English sound, it is a Korean sound :) So maybe sometimes it might sound somewhere in between 'ne' and 'de' but there is no English letter for it.

It seems that you hear 예 as "de" and 네 as "ne". Both 예 and 네 are correct and used for "Yes/OK/是".

I would say not every single actor or actress who will pronounce 데. It's really hard to clarify. In fact, that's another case, (비)안해요, instead of 미안해요that when I was googling it, I found another learner who had same question as me. Thanks.

It's not another way to pronounce it, it's just that a lot of Korean learners think it sounds that way.