sony alpha – Upgrading… and I’ve no clue about which glass to buy?

I am looking at buying a new mirrorless Sony camera, and I’m looking at the options of an A7R III or A7R IV. Now, truth be told, I couldn’t tell you much about the technicalities, but I’ve been told too many times over the years of using my Nikon D80 DSLR (since 2006) that I should “have a coffee table book” or “get published”. Will the price difference in the two cameras really matter for someone with limited technological experience yet eager to really advance oneself?