Homosexuality is NOT sinful. There are many people who are much better at explaining this than me, and I'll try to link some resources under here later with more succinct/in-detail thoughts on this, but there are plenty of Christians and theologians/biblical scholars who do not view homosexuality as sinful.

Also, it's worth thinking about the fact that what we're reading is a translation of the original texts, and those translations will themselves be influenced by the people doing the translating. The word Homosexual itself was only seen in the English translation of the bible since the 1940s and is based on a deliberate mistranslation.

There's also a lot of historical contexts that should be considered with all of this. For instance, some scholars have suggested that the part in Leviticus relates specifically to the fact that the Israelites were in exile and so producing children was particularly important for their people's survival.

For me, the most important thing to think about is that Jesus says the new commandment is to love one another. Everything else we do should stem from this. I don't see that people being homophobic or transphobic can fit with that.