People have their opinions about Bible versions. I'll try to stick to the facts before presenting mine.

In reality, there are many translations in the world, but they are based on two different source texts.

The Geneva Bible, the King James, and Young's Literal Translation are based on the Hebrew Masoretic Old Testament and the Textus Receptus Koine Greek New Testament.

The New International Version, the English Standard Version, the New Revised Standard Version and nearly all of the other modern translations are based on the Septuagint (Greek translation of the Hebrew Old Testament) and Greek New Testaments compiled from Codex Vaticanus, Codex Sinaiticus and Codex Alexandrinus. It's worth noting the Codexes are written in classical Greek as opposed to Koine Greek.

If classical Greek is equivalent to academic English, Koine Greek is equivalent to the English spoken by the majority of people on the planet, including slang words.

So the real choice isn't King James only or modern translations, but rather which manuscripts the translations are based upon.

For myself, I don't trust the modern translations. I feel the Hebrew Masoretic Old Testament and the Textus Receptus Koine Greek New Testaments are the true versions. They're the Bibles the Roman Catholic Church tried to destroy after hiding the Word from the general public for over 1000 years. Only the priests were taught how to speak and read Latin, after all.

When it was clear the English and other language translations weren't going away, and that censorship efforts only made them more popular, the Roman Catholic Church resorted to releasing copies of the "oldest manuscripts" from the Vatican Library and encouraging scholars to base their translations on Codex Vaticanus and Codex Alexandrinus.

Those efforts mostly failed until after the Protestant scholar Tischendorf found Codex Sinaiticus in a wastepaper basket in a Catholic convent on Mt. Sinai, conveniently several weeks after obtaining an audience with the Pope and really took off after Rockefeller took over the majority of the university theological seminaries in the United States.

tl;dr I believe the texts underlying the King James Version are the real Bible, so I'm not King James Only, but I am Masoretic Hebrew and Textus Receptus Only.

I prefer the Blue Letter Bible for online study, because it allows me to see the original Hebrew and Greek words the KJV translation was based on along with their Strong's Concordance listings and definitions.

As an example here's the listing for Ephesians 6:12-

https://www.blueletterbible.org/kjv/eph/6/12/t_concf_1103012