So having read the rules for 4th and 5th and judging them to be wanting I still want to run in the modern era. What current source books will get me up to speed on current events? Preferably keeping it to one or two books.

6th world almanac is probably the main one to look at, i guess. that'll take you clear up to 2072 according to the official description.

not sure if you need much beyond that... if you've seen the 5th edition rules, you presumably have the 5th edition core book, and there hasn't really been a ton of progression since that (yet) afaict.

this
and maybe the Stormfront Book
If you want to know more about Life & Lifestyle than you should get the Attitude book

Hough!
Medicineman

Seattle Sourcebook if you're running your game in Seattle (obviously).

Although, Emergence and Vice move the plot forward quite a bit as well.

most of the books that are not primarily crunch move the plot forward in some way. the sixth world almanac should hopefully cover most of the large impacts up until 2072.

books like emergence and vice i would only recommend if you need more in-depth information about those specific subjects. if you're just looking at a general idea of what happened, they're rather overkill.

Idk if I would say 6wa catches up, more like alternate reality. It's been awhile since I sat down with it and previous books but I know there is more than one place where they stomped on previous canon 6wa is a great book if you ignore previous canon though so well worth reading and buying