"the Paradise I am talking about, you don't die after entering it"
Not every religion considers eternal life desirable. In some forms of Buddhism and Hinduism, for example, the ultimate goal is to leave the cycle of death and rebirth.. not in to paradise, but in to nothingness.
The truly vast amount of literature on both Buddhism and Hinduism argue to the contrary.
Also, the ultimate reality in Buddhism, Hinduism, and (incidentally) mystic forms of Islam, is often described as being beyond words and even beyond conception, so there is a limited amount that could be said about it in ordinary language -- though that hasn't stopped people from trying.
In Buddhism one often hears the teachings described as the finger pointing towards the moon. Language may be inadequate to describe ultimate reality, but it can point to it.
As a Muslim, I can assure you there’s no such thing as mystic Islam. Islam is foremost about clarity, simplicity and straightforwardness in its message of pure monotheism. It does not seek to lure people by mesmerising them with incomprehensible riddles. It hides nothing.
The so called mystic Islam also known as Sufism, is a deviant sect, and is fundamentally a gateway to polytheism, as it borrows many practices from polytheistic religions. In fact, many of the famous ancient sufis have roots in India, where paganism and idol worshipping was and is still prevalent. Hence sufis are adored by Hindus.
Who decides what orthodox Islam and what is heresy?
You'll find Sunnis who think Shiites are heretics, and Shiites who think Sunnis are heretics, and both are major branches of Islam.
Of course you'll find both Sunnis and Shiites who think Sufis are heretics, and Sufis who think Sunnis and Shiites are heretics (or at least don't understand the true or secret meaning of the Koran or of Islam).
And does the Koran have a secret meaning, or only a surface meaning? This important question itself is also a matter of opinion and will differ based on who you ask.
There have also been mystics in Islam apart from the Sufis: Avicenna, the Ismailis, and Alawites spring to mind.
As a non-Muslim, when I see the members of these sects disagree with one another as to who is a "true Muslim" or what is or isn't Islam, what reason do I have for believing any one of them over the others?
Their appeals to scripture, lineage, famous commentators and the like are not very convincing both because as a non-Muslim I have no reason to believe in any of them and because you can easily find other people who claim to be Muslims making pretty much the same appeals in support of completely different conclusions.
At this point in my life, anyone who considers the Koran their central scripture is a Muslim in my eyes.
If you have a better definition that doesn't rely on appeals to scripture, to lineage, nor to the authority of some person, I'd love to hear it.
>The so called mystic Islam also known as Sufism, is a deviant sect, and is fundamentally a gateway to polytheism, as it borrows many practices from polytheistic religions.
This illustrates that you have a fundamentalist streak in you: you've described a form of Islam you don't like as being "deviant". You're gatekeeping Islam.
I kept reading your comments above till reach here. Your knowledge about Autism is pretty narrow and region-centric. No one considers taking drugs and shaking as Sufiism. It's opposite of that. Sufism is all about self discovery and connecting to God with Dikr. The Dikr as described as in Quran as satisfaction of heart.