Anyone into music theory in here? Trying to make a cover of Princess Die

[Super 863]

I'm not sure if I'm posting this in the right category – sorry if that's not the case!
Well, gonna keep this as brief as possible – I've been producing music for a few years now, learnt a little of music theory on the way but far from being good in playing anything by ear.
I got this idea of covering Princess Die for a while now but there are so many versions with different chords floating around the internet and I wanna make sure I'm playing as close to the original as possible. Tried three different versions but they were all v different (or even off) so I'm wondering if there's any music nerds in here who would be kind enough to help. Even the song key only would help a lot already. Thanks in advance