If you want to change the game, change the value of the shot.
The problem is not how good the players are getting at threes. Is how lopsided the valuation of the shots is. A good shooter makes 50% of their twos. To make the expected value the same, a three point shooter needs to shoot 33%. Which isn’t even a good number, nowadays.
For a shot that’s only 17% percent harder, it’s valued 50% more. It was only a matter of time until shooters were going to spread the court and light it up.
So to fix the problem, I’d suggest addressing the point value. While it would be a mess on paper, value the old 3’s at 2.34 points. You don’t have to repaint anything, and you naturally shift the game back to what it used to be. Too much post play at that number? Bump it to 2.5.
The scoreboard may get messy, but it may be worth it. Plus, you can keep the game style steady by adjusting the points as needed before the start of season.