I was the one who shared AlyssaVT's guide. I kind of regret doing that, as I hadn't tried it out for myself back then. After doing those voiceless excercies for a few weeks I ended up with a sharp pain in my throat, and then I became more sceptical and looked into what others had to say about it.

From what I’ve read on the transvoice subreddit and discord, it seems like guide's focus on anatomy (training the throat muscles, raising the larynx) is outdated, inefficient and potentially harmful. The focus should instead be primarily on changing two specific sound qualities, size and weight, and getting the two in balance to achieve what's called fullness. That is done by first training your ears to hear the individual size and weight aspects by listening to demonstrations of other people changing those aspects. Then you move on to trying to change the size and weight of your own voice by actively listening as you're doing voiced exercises. It's very important to keep the throat relaxed while doing this, you're not supposed to push beyond what's comfortable.

I've found it really helpful to listen to voice clips by Selene and this video by TransVoiceLessons. The charts shown in the video were also nice, they helped me better understand how weight and size work together.

Btw, I've also read that L's guide contains a lot of outdated and bad information, such as the swallow and hold excercise. Doing that excercise is at best a waste of time, and at worst can cause serious damage to the throat. Here's a detailed overview I found of everything wrong with L's guide