I've read all 7 of them, in French (since that's my mother tongue) several times over the years. Great books

You'll be ok if the last one isn't available, it's almost an add-on. Although they do follow on from each other, each volume is pretty much self-contained. I was given the 1971 edition some 30 years ago

and only 6 volumes are listed there - the first 6 books were out between 1955 and 1960; the 7th only came out much later in 1977. To this day, they are still amongst my favourite books.
You shouldn't really expect them to be like Game of Thrones though. I've seen Druon's books described as "the research of the historian combined wit the art of the novelist" and I think it's fairly apt.