Go back to the 64-bit client.
I've never noticed TurboBoostSwitcher fail to make the switch when manually set to do so. You can run this command in the Terminal:
Do it first while you're just running your web browser and Crossover, then launch LOTRO (enter a game world with a character) and look at the Terminal window. You should certainly see the metrics jump up once the game is running but CPU usage should not go over 100% with TurboBoostSwitcher set to disable the Turbo Boost of your CPU. Don't run that Terminal process for very long, it is very resource-intensive itself – just get your metrics for no-LOTRO with and without Turbo Boost disabled, then with-LOTRO with and without Turbo Boost disabled, then close the Terminal window to quit the "top" process.
edit: Just FYI, here's a dump of my top process going from running about 10 applications including Crossover, then launching LOTRO, entering a game world, then logging out and quitting LOTRO. This is from a 2019 3.6GHz quad-core Intel iMac whose CPU has no Turbo Boost capability.
Code:
Last login: Mon Aug 22 12:07:31 on ttys000
JohnMHammer@JMHs-iMac ~ % top -F -n0 -s3 | grep "CPU usage"
CPU usage: 4.47% user, 22.38% sys, 73.13% idle
CPU usage: 2.5% user, 3.4% sys, 94.89% idle
CPU usage: 0.73% user, 2.38% sys, 96.87% idle
CPU usage: 4.44% user, 3.4% sys, 92.51% idle
CPU usage: 6.60% user, 4.37% sys, 89.2% idle
CPU usage: 24.61% user, 18.94% sys, 56.43% idle
CPU usage: 16.36% user, 9.12% sys, 74.50% idle
CPU usage: 15.77% user, 5.75% sys, 78.47% idle
CPU usage: 16.95% user, 3.62% sys, 79.42% idle
CPU usage: 0.82% user, 1.32% sys, 97.85% idle
CPU usage: 0.90% user, 1.56% sys, 97.53% idle
CPU usage: 1.6% user, 1.81% sys, 97.11% idle
CPU usage: 2.55% user, 3.70% sys, 93.74% idle
CPU usage: 1.31% user, 1.64% sys, 97.3% idle
CPU usage: 9.62% user, 4.19% sys, 86.18% idle
CPU usage: 5.34% user, 2.38% sys, 92.26% idle
CPU usage: 3.4% user, 2.55% sys, 94.39% idle
CPU usage: 2.38% user, 2.30% sys, 95.30% idle
CPU usage: 2.38% user, 2.38% sys, 95.22% idle
CPU usage: 1.48% user, 1.80% sys, 96.71% idle
CPU usage: 2.30% user, 2.13% sys, 95.55% idle
CPU usage: 2.46% user, 2.38% sys, 95.14% idle
CPU usage: 5.43% user, 5.93% sys, 88.63% idle
CPU usage: 43.99% user, 8.55% sys, 47.45% idle
CPU usage: 47.4% user, 21.51% sys, 31.44% idle
CPU usage: 7.46% user, 5.41% sys, 87.12% idle
CPU usage: 10.4% user, 7.65% sys, 82.30% idle
CPU usage: 4.61% user, 7.41% sys, 87.97% idle
CPU usage: 5.9% user, 7.39% sys, 87.51% idle
CPU usage: 4.53% user, 7.74% sys, 87.72% idle
CPU usage: 12.24% user, 12.24% sys, 75.51% idle
CPU usage: 7.88% user, 7.80% sys, 84.30% idle
CPU usage: 11.53% user, 10.21% sys, 78.25% idle
CPU usage: 67.2% user, 12.30% sys, 20.67% idle
CPU usage: 38.68% user, 8.55% sys, 52.75% idle
CPU usage: 16.85% user, 9.78% sys, 73.35% idle
CPU usage: 6.23% user, 7.22% sys, 86.53% idle
CPU usage: 10.86% user, 8.47% sys, 80.65% idle
CPU usage: 24.97% user, 10.27% sys, 64.74% idle
CPU usage: 21.58% user, 9.71% sys, 68.69% idle
CPU usage: 9.20% user, 7.39% sys, 83.40% idle
CPU usage: 4.43% user, 7.64% sys, 87.92% idle
CPU usage: 9.79% user, 8.55% sys, 81.64% idle
CPU usage: 23.99% user, 7.97% sys, 68.3% idle
CPU usage: 26.66% user, 7.98% sys, 65.34% idle
CPU usage: 38.89% user, 9.29% sys, 51.80% idle
CPU usage: 26.33% user, 9.30% sys, 64.36% idle
CPU usage: 16.44% user, 8.79% sys, 74.75% idle
CPU usage: 31.2% user, 6.58% sys, 62.38% idle
CPU usage: 30.27% user, 8.44% sys, 61.27% idle
CPU usage: 26.27% user, 8.64% sys, 65.7% idle
CPU usage: 21.16% user, 8.81% sys, 70.1% idle
CPU usage: 17.96% user, 7.95% sys, 74.7% idle
CPU usage: 24.38% user, 9.44% sys, 66.17% idle
CPU usage: 20.82% user, 7.57% sys, 71.60% idle
CPU usage: 16.80% user, 6.75% sys, 76.44% idle
CPU usage: 16.91% user, 6.73% sys, 76.35% idle
CPU usage: 22.28% user, 7.40% sys, 70.31% idle
CPU usage: 22.28% user, 8.63% sys, 69.7% idle
CPU usage: 8.79% user, 7.64% sys, 83.56% idle
CPU usage: 8.4% user, 7.38% sys, 84.56% idle
CPU usage: 10.93% user, 9.4% sys, 80.1% idle
CPU usage: 14.50% user, 8.57% sys, 76.91% idle
CPU usage: 5.43% user, 3.62% sys, 90.94% idle
CPU usage: 6.33% user, 3.45% sys, 90.20% idle
You might also want to set TurboBoostSwitcher to sample its data only once every 10 seconds, that should be plenty good enough and will reduce its demands on your system resources a bit. You can set it to something more frequent like once every 1 second when you're actively testing something but for general use a 10-second sample interval is more than good enough especially since you won't pay any attention to that information at all once you're satisfied with your Mac's performance with LOTRO and other things.