Google sheets PRO needed (can't be afraid of scripts!)

EDIT: Getting LOTS of responses. Most of you gave yourself 3 or 4 stars in Excel. This is a 5 star job, I promise. If you REALLY know what you're doing, send me your whatsapp number when you ---------- eelance gig - pay is $250 USD - I come with plenty of GOOD Filipino references, no worries.
If you need hourly pay instead, talk to me and we'll see what can be done. (Maybe)

I have a very complicated google sheet that I am an "editor" of. I do not own it, and I am technically not allowed to share it. I tried downloading it to make a copy of it, but because there are two files that reference off each other, it didn't work. What do I need?

I need the 2 files copied over to me, where I am the owner of them, along with a couple changes.

-See exactly what the scripts do, other than calculations. I think they send data somewhere, I need to make sure nobody is getting or seeing the data from the new files but me.
-remove the existing branding
-make minor edits in how some of it works, change locations, ---------- thing major, I need 99.99% the same.

I may be convinced to replicate this into something other than g-sheets (not excel) if that makes it easier, but the burden of proof will fall on you to prove that it can have the exact same functionality and to make sure a dummy like me can still use it. Airtable? ClickUp? I still prefer g-sheets for now.

I cannot share access to this file. If you are interested we can do a screenshare and I can show you the file over zoom. If we both agree to proceed, I'll give you access to a google account that the files have been shared with and you can work on it from there. We'll be communicating over whatsapp, so have that handy. I don't use skype.

Thank you,

Leo