I think you and I are a lot alike. It seems like some people have more of a challenge than others when it comes to conscious creation. And 100% agree about holding space for yourself, so important. The things you’re talking about being important can’t be distilled into a technique, it’s really the relationship with oneself which can be its own challenge. Especially if the relationship with yourself isn’t a great one.
Emotional suppression sucks. I have a bad habit of it as well. You mentioned Neville and I’ve been re-reading some of his books. An important thing that helped me was when he states those emotions will always happen, but it’s how you respond to them and what replaces them. Never about not making them happen or thinking about them. It’s helpful to think of everything as autopilot. It’s not moment to moment that dictates the manifestations, it’s those seeds you plant in your subconscious that grow. If you go to bed every night and meditate on what you desire that’s a strong emotional implanting and then the various negative thoughts or feelings throughout the day might chip away at it. But you do it again the next night and you reinforce your desire. I know how you feel though, it’s a weird obsessive worry that when one negative thought or emotion slips by it’s going to derail the whole manifestation.
I think backing off of that stuff is a good idea. At the heart of it manifesting is dead simple in principle there’s not much to “get”, so excess info doesn’t really help. But I do think nightly meditations help before going to sleep. Just focusing on what you want and making that intention known so your subconscious has a clear path when the day starts in the morning.