You did not specify the current tier. Having reached the Legend tier by level 77 I have had to deal with the issue. I have had success with Saint Andrews Front 9, and PGA National Back 9 and Front 9. For a while I used to be very successful at Pebble Beach Front 9 and Torrey Pines South Front 9. While I scored a few 30-31 shots (Tour Master level) on most courses and a few 28/29 on those mentioned above, I can tell you that the perceived difficulty depends a lot on the clubs you use, the balls, and also how the winds are set up.
Some courses are par 70, so if you get a par you already start from 70 which helps lowering your average, assuming that you are not below 70 already. The Front 9 at Olympic have par 34 (so if you can get par it is like scoring a 68), but that course is tough and requires powerful clubs. Often the lower par is because some very long par 4 instead of being par 5 are used as par 4. And if you don't have powerful clubs, you will likely not reach the greens in regulation (i.e. 2 shots for a par 4) .
I have always played in the only set up available when I play single, so for me at Tour Master level that meant Hard pin locations, Very fast greens (11) and moderate winds. I entered a few tournaments, but seldom.
One big problem with tournaments is that, one has to give up the costume, and that takes away some power from the driver or some precision from irons, or a tad better sweet spots for this or that club. Costumes help players who cannot buy the best clubs and balls, even if moderately, but doing without means sometimes learning to use the clubs differently.
I was told many times that the best way is when a club set up courses using much easier settings, but that is foreigner to me as my club basically ceased to exist shortly after I joined.
One thing I can tell you: since I achieved the Legend tier relatively fast (level 77), now I face a very tough existence. When one reaches a higher tier, golf courses become all longer, greens faster, etc. But that would not be a big deal. However, now I need to play very long holes (par 5 are even 600+ yards) and I cannot get the top clubs until I reach level 90-95+. That is a problem for now basically I cannot compete. It is likely I will quit the game as it is just a waste of time after another. And I am not interested in playing tournaments, CCTH, etc. It is funny and sad at the same time that I play level 100+ players who are just Tour Pro or Master tier, play shorter tees than I have to, and have the top clubs and balls! And here I come, starting from far behind with clubs that are 1-2 levels below theirs. Quite stupid that Topgolf decided to anchor the clubs to the levels and not the players' tiers.
When all is said and done, your best bet to lower your average is to buy the top balls. It is that simple. It makes a huge difference to have a ball with spin 4.5 or even 5 vs a ball with a spin of 1 or 2. If you could get the wedged with high angles (high trajectories so that when the balls land they barely jump around). Same thing with woods and irons.. pay attention to the trajectories (high is better, medium is the worst as with the latter balls will run a lot which is horrible when you need to get to the greens and stop the balls)
Depending on your level and your equipment, I would avoid the courses with very long holes: the holes may not be terrible, but they are so long that you would never reach the greens in regulation, in particular with headwinds and, unless you can hole your shot, you will have a hard time to even achieve par. Firestone has some incredibly long Par 4s, Olympic is hard too, Chambers Bay has a few of those too, and more...