I would recommend starting with the gospels (the first books in the new testament: Matthew, Mark, Luke and John).

About the feeling of unease, I think it’s natural. I am uneasy when confronted with my own failure. That’s life, a journey with many hurdles to be overcome, many of them my own shortcomings. But I want to be better. So I need to acknowledge my faults.

This also shows what love means. If I were perfect, it would not be hard to love me. But the people that love me do so despite my failures. So does God. And that makes love truly valuable.

Letter from Paul to the Romans 5:6-11 NIVUK

[6] You see, at just the right time, when we were still powerless, Christ died for the ungodly. [7] Very rarely will anyone die for a righteous person, though for a good person someone might possibly dare to die. [8] But God demonstrates his own love for us in this: while we were still sinners, Christ died for us. [9] Since we have now been justified by his blood, how much more shall we be saved from God’s wrath through him! [10] For if, while we were God’s enemies, we were reconciled to him through the death of his Son, how much more, having been reconciled, shall we be saved through his life! [11] Not only is this so, but we also boast in God through our Lord Jesus Christ, through whom we have now received reconciliation.

https://bible.com/bible/113/rom.5.6-11.NIVUK

I feel some good starts could be Martin Luther’s “Small Catechism” and “On Christian Liberty”.

Edit: maybe a bible studies group of an historical church (Lutheran, Presbyterian, Catholic, Orthodox, etc. )

Humans are biologically programmed to have a euphoric experience when presented with something beyond their ability to understand. For example contemplating the massive expansive of the cosmos and how it all began etc.

As we get older our brains take damage and slow down resulting in a coping mechanism very similar to the above mentioned phenomenon.

As we approach death and old age we tend to shift towards religion as a way to both biologically and psychologically cope. Even the most avid atheist will see and feel that shift inside themselves. Stress is also a factor.

That is not to say that god isn’t real. I dont know that and no one else does either. This could all be his plan for everything. Or it could just be a damaged and stressed brain trying to cope.

On the plus side… Religious people love to talk about what they believe. You can get a bible just about anywhere for free. There are thousands of online videos of sermons and talks. All the tools you are looking for are out there. But you will also probably be drawn to an active organization because again humans are biologically drawn to form groups of like minded individuals as a protection mechanism.

Christianity, as an organized religion, is rife with issues and inconsistencies. In some ways that’s reflected in the extreme diversity of the religion. You’d literally need a spreadsheet to keep track of all the denominations, splinters, and factions within Christianity because none of us can agree on anything. To make matters worse, for much if it’s history, the church has been a tool of oppression; completely antithetical to the teachings of Jesus that it claims to embody. Because of that, the church – and by extension Christianity – get a lot of well warranted criticism.

However, that’s not to say that the church as a whole is inherently bad or lacking in value. There are plenty of Christians who genuinely believe in God and want to live in a way that exemplifies the teachings of Jesus.

If you want to know what it means to be a follower of Jesus, there are two passages in the Bible I would highly recommend. The Sermon on the Mount (Matthew Chapters 5-7) and The Sermon on the Plain (Luke 6:20-49). In those sermons, Jesus outlines what [we believe] God expects from us and what it means to be his followers.

To address a couple of your other questions:

Sin

Sin is the things in our lives that separate us from God. Some Christians make the mistake of trying to distill sin down to a list of “Do’s and Dont’s”. It’s really a lot simpler than that. Read the gospel passeges I mentioned above and think of “sin” as failure to live up to those ideals. It’s something we all do at times.

Heaven

Scripture does support the idea of an afterlife and “heaven”, “paradise”, etc. are mentioned on numerous occasions. The details are vague and honestly, some Christian traditions place way too much emphasis on “heaven” as though we were given life on earth only to speed run our way to death and the afterlife. That sort of thinking makes light of the miraculous gift that is this life.

Hell

Much of what you probably think of when you hear the word “hell” comes from fiction (think Dante’s Divine Comedy) rather than from the Bible. English translations that refer to “hell” are actually referring to one of several different places depending on the context. Scripture is even more vague on this than it is on “Heaven”. Personally, I do not believe in “Hell” as a place of eternal torment.

I hope this is helpful. My faith is an important part of my life. It didn’t start out that way though. I nearly gave up on Christianity altogether because I grew up in the church and saw so many things happen that were the opposite of Jesus teachings. Eventually I learned that not all Christians are like that.

I’m no theology major but I’m happy to answer any questions to the best of my ability.

Reading the Bible.

As someone in a similar boat, I hope you find the answers you’re looking for.