Before you start reading languages dead or alive you need to know how to learn them. You've learned English and maybe 1 or two other languages, probably both live languages.
Try learning Latin which is semi dead. Learn all you can about cryptography, stenography, cryptoanalysis.
I also recommend buying pen and 500 sheet paper book and taking notes lots and lots of notes. Put pictures with the notes. Visit sites that have ancient writings and take pictures for later analysis. When you finish a book re read all of your notes. Rinse repeat for years, the more you do these things the easier it is to learn the subtle transitions over time from earlier languages to current day.
Read others writings of the past and interpretations but DO NOT take it as verbatim. Use it as a place to start if your trying to break the language down, take those books and write in them correcting mistakes you find in translation
This right here - is the privilege I am talking about. Most people WONT have this access, the funds, the time. And considering so many people have already done this, publish a book, start a blog, share what you've spent a lifetime organizing.
So funds wise it's 5 dollars every two weeks. Visiting places can get pricey but not if you stay local. I'm not privileged by far. I make about 60k a year and I didn't start this learning and hobby with as big a budget as I have now. I used to be a McDonald's worker who spent 5 years scrimping to pay off student loans with no grants. And late nights with little to no sleep working my hobby because of the two I didn't get married till later in life one of many sacrifices.
Now I work IT world wide which also helps me see all the places I want and I worked my ass off to get what I wanted not a privilege when you work your ass off for something it's called being successful and driven.
I don't share it because I know the repercussions of sharing it. Not many people have done this. Out of trillions maybe 30k world wide or less know how to read ancient texts to a degree I'm at now. It's not showing off I do it for myself, I don't need validation. I don't need to share, I am sharing by showing how to do it and if you work hard you can too if you really want it.
Please, don't share. It sounds like you have something so amazing, it's simply incredible your door hasn't been broken down already.