I find 'comfort' in all manner of things, but do Christians/believers have an abundance of it? I doubt it, they seem consumed by doubt, unworthiness, submissiveness and/or ignorance. I don't think their take on life, the universe and everything is anything to be envious of.

I'd love to help, but I don't relate to the the words 'spiritual' & 'universal' .
You'd have to define them before I could comment further, sorry.

Be the change you want to see in the world. There is nothing wrong with having a sense of spirituality that grounds you and gives your life a sense of purpose.I disagree that Christians have a sense of peace and happiness. Christianity was created by people, and all people are a complete fucking mess. The human animal will suffer in the world it's guaranteed. You never go into where you stand on the political Spectrum, I'm on the liberal side and find limiting the exposure to news and negative Facebook clickbait articles is extremely helpful for my peace of mind.

It is much simpler than we make it to be.

The best and most comfort is in the freedom of all kinds. Freedom from cable news, freedom from payroll, freedom from financial dependency, freedom from an unhappy marriage etc. Freedom of religion is the best among all.

What is “something spiritual”?

“Something universal” sounds to me like what I understand is the goal of physics - The Grand Unified Theory, if I have that correct.

The universe is natural. Most Goddites are claiming a supernatural “dimension” or whatever they choose to call it is in existence. That’s what they claim “spirit/spiritual” to be/made of, as far as I hear them describe it.
There’s no proof of the existence of anything supernatural - almost by definition!

The only religious explanation of “spirit” I have heard is the Buddhist definition of spirit as the mind - conscious, subconscious and “deeper”.
The “deeper” has no proof of course, but we know the reality of the existence of the conscious and subconscious mind.

The mind as we know it is an integral part of a living body.

I’ll accept that life is “something spiritual” going on in the universe.

Anything “supernatural” makes no sense and reeks of GODISM !!

I recommend Buddhist concepts like Karma if you seek comfort.

Reincarnation is another.

There seems to at least be some valid evidence for some form of reincarnation.

Karma is a good and useful concept imho, it makes sense and there’s no evidence for it, but that may satisfy your thirst for a supernatural explanation...

Thus, BUDDHISM offers you comfort in reality and “super-reality”!

I believe your position is correct.
unlike most other mammals we have a very long childhood.
due to this we expect that there are powerful controlling beans that will provide for our every need. of course is our parents, as we get older we realize that our parents are flawed people like ourselves. the need is great the god-shaped vacuum is there, so we create a all powerful parent without human frailties. we can assign the attributes to the God as we see fit. the Roman assigned to their gods based on the values of their society.
the Jews and Hindus selected gods with attributes that reflected their society.
clearly if horses had a god it would look like them and reflect the values of their society.
knowing this does not free us from the god-shaped vacuum, it's still there.
it is my belief we will fill it with something, science, civil rights, or The voices in your head

This will be of no help to you at all but I've just learned to deal with feeling lost as best as I can.