You mention Nehushtan often.
I am asking you to consider and weigh what I am about to share. This is probably where I get kicked off the site since I am sure many today would disagree but I must say it: Mysticism can also be a form of idolatry. I was swept up in vibrations of crystals as a form of healing. There are huge stones in my yard that I use to lay on in the warm sun believing that they somehow pulled negative energy out of my body. I am sorry but this is no different from...Nehushtan.
It is worship of something other than God. I was caught up in it until He told me it was wrong to put faith in those things. Maybe you are not holding those things to a high standard above God as I was...but I do care about you and wanted to share a hard truth I had to acknowledge.
Exodus 7:11 KJV
[11] Then Pharaoh also called the wise men and the sorcerers: now the magicians of Egypt, they also did in like manner with their enchantments.
Romans 1:25 KJV
[25] Who changed the truth of God into a lie, and worshipped and served the creature more than the Creator, who is blessed for ever. Amen.
Mysticism is a major problem in the church today and is leading many away from God rather than toward Him.
Definitely is a problem in the Church today, a lot of Christians mix up their Jesus spiritual activities with non-Christian spiritual activities, and light and darkness don't mix, it can get pretty messy, someone might go to Church one day and then go to a psychic or witchdoctor the next, or go practice some new age activity, there are 2 sides to the supernatural, the supernatural that Jesus taught us, are the powers of the Holy Spirit, the Light, then as you say Pharoah used the otherside of the supernatural, he looked towards the powers of darkness, the powers of witchcraft, the demonic powers of Satan, and used sorcerers, magicians, and God knows what other forms of witchcraft he looked to.
Of course the supernatural is very important though, it is how healings, resurrections, praying in tongues, prophecies and other wonderful stuff happens, but we are meant stick to God's ways when it comes to the supernatural through the Holy Spirit. And you know being still in His presence, taking deep breaths, pauses, silence, meditating on what you read in the Bible an hour ago are good practices when you spend time with God, they are great ways to relaxing and taking your mind off the world and focusing on Jesus, God's word, letting him speak to you in one way or another, whether if it's audible hearing God by ear or hearing God's word through your heart, or the Holy Spirit bringing something to your understanding, or by even seeing, it's so very important.