Marin recommends 1. Nf3 d5 2. g3 Nc6 for Black:

https://www.modern-chess.com/1-nf3-d5-2-g3-nc6-practical-solution-for-black-1h-a...

Then there is 1. Nf3 d5 2. g3 Nd7 recommended by Krykun:

https://www.modern-chess.com/meet-1-nf3-with-1-d5-complete-repertoire-against-2-...

Modern-Chess is having a 60% off sale. They usually take off another 10% if you buy more than one title.

Another option is 1Nf3 f5. This avoids some ideas for White that one might find annoying, for example, 1d4 f5 2Nc3 Nf6 3Bg4 or 1d4 f5 2Bg5. Black seems to be doing well in the Leningrad Dutch and this might be a safe way to reach those positions.

1Nf3 d5 2g3 c6 with Bf5 or Bg4 to follow later is solid, but not so adventurous, IMO.

I'm a bit sad to see this game/defense getting attention as it has been effective for me for a few years and had some surprise value.  It is well-covered in Raetsky's unfortunately-titled "No Passion for Chess Fashion" as well as in Wisnewski's "Play 1...Nc6" and cursory coverage consisting of a single game by Raetsky in "Modern Chess Openings: Black" by Gary Lane.

A year ago I played a 1900-something USCF player in a G/90:
1.Nf3 Nc6  2.d4 d5  3.g3 Bg4  4.Bg2 Qd7  5.O-O O-O-O  6.Nbd2 f6  7.c3 e5  8.dxe5 fxe5  9.Nb3 h6?  10.Be3 Bh3  11.Bc5 Bxg2  12.Kxg2 Nf6  13.Qc2 Ne4  14.Bxf8 Rdxf8  15.Nbd2 Ng5  16.Nh4 Qh3  17.Kh1 Rf6  18.Ng6 Re8  19.Rae1 Qh5  20.Nh4 Nh3  21.f3 e4  22.f4 Nxf4  23.c4 Nxe2  24.cxd5 Rxf1  25.Nxf1 Ncd4  26.Qa4 Kb8  27.Ne3 Rd8  28.Nhg2? Nf3  29.Ng4 Nxg3#