I do understand the desire to enter dreamtime.
For me personally it is the other way round. I was born with an open door and my everyday desire is to close the door
Permanent visions cause problems when you live in central europe
In modern europe you wont find a teacher like if you live in a tribe. So.. i learned a few things the hard way...
I do avoid substances, except for an annual traditional ritual. I do not buy stuff, i just take two weeks off from work and leave home for the forest. It is a dream quest in a very traditional meaning. Dream quest means, there is a call, a starting point and probably a theme.
To be honest, i doubt that the usage of any DMT substance does anything good if not guided. At the end of the day it causes more confusion then insight. Flooding awareness with impressions doesnt help unless you find and follow the yellow brick road. Thats why there has to be a call and a starting point. And from the starting point there is a path, a unique path leading to the dream quests result where real transcendence, healing or problem solving is happening.
All those impressions are worth nothing if you are not able to be in a dual awareness. To hear a voice is one thing, to recognize the speaker is a completely different story. Beings will come and show interest, ask or answer questions but it is necessary to recognize them with the everyday mind. This should be a step by step development, because the goal is to keep the waketime and dreamtime together and maybe even develop the resulting abstraction. Without this the result is either an insane mind or and insane body. Without keeping the different awareness's together it is like tearing your aura apart, creating "a energy bleeding wound" which is attracting the dreamland sharks, the shadows. Untrained such an encounter cant be dodged. Over the years i have seen many good people fall for this. Without proper actions and at least one totem the journey ends here for a looong time. Thats why we usually first find a familiar spirit and then proceed further. Really, its like having sex with strangers and without protection. Once a shadow was able to "dock" into your energy it will take years if not decades to get rid of him. We dont live long enough for such time sinks.
Oh, btw. It is known that "dreamland bodies" can be cut with sharp objects like a dagger or sword or claw. The wound will be on the physical body. Ever woke up with an unexplainable scratch ?
Think, then travel.
When done proper there is no need for any substances. By then you are quite deep into the rabbit hole already
Since i observe this all for a few decades now i can tell that it is all about heart. The chakra system is one of the best systems for psychonauts on this planet. It is, imho, worth to study it. While many say the third eye is key to dreamland i say its not. The eye is the visual sensor, but the real action is in the heart. Actually the colorful impressions in the forehead chakra are rather distracting then helpful. All is in the heart.
Hope that helps a bit.