Text Feature Dragging Down AE

Sorry for the delayed response. Are you still having the issue?
Feel free to reach out. I am moving this thread from Bugs to Discussions for now.

Thanks,
Nishu

 here's the project 

I originally had it set up with Dancing Script.ttf. I changed the font to Brush Script with the same result. It wasnt until I turn Faux Bold off that I saw a remarked improvement in performance. Looks like your set up is different than mine, so it could be all of my particulars (M2, Sonoma, etc) creating the issue.

Is this happening with any font or a particular font?

There was an issue with the Apple designed typeface San Francisco awhile back.  I can't remember if it was SF Pro, ST Mono, or SF Compact or all of them; however, that should be resolved.

Are you able to share the project (even if it's just the AEP without any source footage)?

I just tried Faux Bold with the font Jay Gothic URW from Adobe Fonts on a 16-inch M1 Max MacBook Pro 32GB/1TB under macOS Ventura 13.6.3 with After Effects 24.1.0 while showing the Composition Profiler and render time is 1ms with or without Faux Bold enabled in the Character Panel.

What happens if you use Skew instead (Animation > Animate Text > Skew) at a value of about 12?