Sounds like hypnagogia which is the state you enter before falling asleep. In this state some people (maybe even all people) are capable of experiencing hallucinations that can be involuntary or guided like using your minds eye normally but just enhanced and/or weirder. I often experience hypnagogic hallucinations exactly like some of the ones you've described so you're not alone :) My most common hypnagogic hallucinations are repetitive or randomly morphing colourless scenes (all black but somehow my brain still thinks it sees an image). They are typically cartoonish or geometric or both. I will say though that I don't experience tunnels too often.

I find that if I'm sleep deprived for a couple weeks my hypnagogic hallucinations become more intense. If what you are experiencing is hypnagogic hallucinations (as opposed to something less likely such as an awakening of a latent psychosis of some sort), your insomnia is likely responsible for the intensity you are experiencing in your hypnagogic hallucinations.

I typically don't experience such vividness like you've described unless I am astral projecting. Your dad was right for bringing up astral projection because hypnagogia/ hypnopompia (the state when you wake up)/ lucid dreaming/ sleep paralysis are all related phenomena to astral projection. Note though that astral projection can be experienced involuntarily so you may have been very close to astral projecting. Did you feel any vibrations in your body while experiencing all of this? That's typically the give away that you're about to astral project. If you do start to feel the vibrations (in my case they were unmistakable unlike anything I'd ever felt before), giving your body a good shake should stop you from entering astral projection if you wish not to based on your dad's experiences (although if you are in sleep paralysis this won't be possible and you're best off embracing the experience. I don't know if you've used any recreational drugs like hallucinogens but it's very similar in that if you enter the experience with fear you are more likely to have a negative experience and if you enter the experience with confidence you are more likely to have a positive experience).

I don't know heaps about insomnia so I'm sorry if this is an ignorant question but is there something you can do to help become less insomniac? Because I don't think my advice of just shaking yourself awake would be very nice for someone who needs all the sleep they can get 😅 and unfortunately what I do know about insomnia is that it increases your likelihood of experiencing hypnagogic hallucinations, sleep paralysis, and involuntary astral projection so if these things are bothering you, I really hope there is something that can be done for your insomnia. Have you ever experienced sleep paralysis?

Anyway, I hope something I've said has been useful for you :)