Edit: there is currently a way around this achievement. Play a scramble match with your difficulty on legendary and a partner on easy. If you finish under par that way, you'll unlock it. Just pick your partners ball every time.
This achievement is going to be difficult regardless, but there are ways to make it way easier.
Starters: pick clubs with large swing planes and high forgiveness.
Swing planes increase the width your swing can stay within before things get wonky. These tend to also give you a lot of shot shape, as you can then hit across the ball, creating purposeful, controlled dramatic fades or pulls.
Forgiveness affects how badly the ball reacts when you miss your swing plane/have bad tempo.
I used the starter clubs across the board. They cost no money and have pretty good forgiveness.
Driver: 11° HBS Classic F01
3 wood: HBS Classic F01
5 wood: HBS Classic F01
3-9 Iron: HBS Classic F01
PW/GW/SW/LW: HBS Classic FS8
Next, course. TPC Boston from the red tees is barely 5200 yards. I drove the green on 3 holes for eagle putts, you are basically chipping/pitching to the green except par 5s, which are usually 100-150 yard approach shots. On top of this the greens are big and mainly flat. I recommend the second pins. The first hole gets placed worse, but it's away from the false front, and MANY of the other holes move away from difficult bunkers. I've done it on both, I feel the second set will benefit most people, but the first isn't terrible.
Set your course conditions to completely easy, so no wind, very slow greens, very soft fairways/greens, and noon with no clouds so you can see the green breaks easier.
When on the course ready to hit, press B to bring up your yardage book. This will show your character with an arrow for where your facing and triangulated distances to the pin. Use this along with the carry distance of your clubs to determine your club strategy. When hitting your second/third shots on par 4s and 5s, press R1 from this yardage book screen to focus on the green. This will give you distance to the pin.
Now the hard part, hitting smoothly.
First: CALIBRATE YOUR SWING IN TRAINING MODE. It will alter the timing for you, so what feels comfortable for your is the timing it wants you to shoot for. Focus on a straight swing path. bad tempo but a good swing path gives you a pretty playable miss. Bad swing path and bad tempo is when you get crazy slices or pulls. If you tend to have a fast tempo, aim left, and slow, aim right. For putting, lightly pull your stick back. The power estimation it gives you tends to be a little heavy handed on these flat greens. I will purposefully hit a percentage or two under on long range putts so I don't end up outside of an easy second putt. I tend to pull lightly back and then sort of jab forward. It works well for my tempo. Find what's comfortable.
Some notes on the automatic club selection: Club up from the rough based on your lie percentage (seen in the top right corner), the game will give you a club that would travel to the pin on a perfect lie, not a 67-77% heavy rough.
Lob wedge pitch shots are way shorter than you expect. They were the most finicky part of the game for me.
If you game auto sets you to chip, club up once, maybe twice. It won't account for the very slow greens, so it'll be short.
Pay attention to how your ball bounces when it lands by the hole, the green breaks in the direction of the bounce.
Be wary of when you're hitting off hills. The direction the slope goes, the ball will go. So aim to compensate for this.