Beyond 'Too Loud/Quiet': Hidden Loudness Compliance Pitfalls for Beginners?

Hey everyone, Annika here, an editor still very much learning the ropes with audio delivery, specifically around loudness and compliance. I've been wrestling with a few projects recently, mostly commercial spots shot on an ALEXA Mini and some documentary work using an a7S III, where audio mixdowns keep coming back for revisions related to loudness. I'm using a MixPre-10 II for field recording and generally trying to hit the right LUFS targets, but it feels like there's something I'm missing beyond just the overall level. I'm checking True Peak and LUFS, and while I understand the basics of 'too quiet' or 'too loud,' the feedback I get sometimes feels more nuanced. For those of you with more experience, what are some of the most common 'Loudness and Compliance' mistakes you've seen beginners make that lead to rejections or frustrating revisions? Beyond just being 'too quiet, too loud,' what are the subtle pitfalls or oversights that really trip people up when it comes to audio delivery standards?