T12 Fluorescent ballast bypass not working

You must follow the Electrical Code.

NEC 110.3(B) Installation and Use. Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.

You did not read the instructions, so you broke the law. I know because if you had, it would have worked (or you would have realized you bought the wrong thing).

The problem

There are at least four kinds of LED "tube" on the market.

• Plug-n-Play: These require a fluorescent ballast to be present. They may have particular requirements to the ballast. With these, you can easily rollback to real fluorescent once you realize LED replacement "tubes" are a stupid product. This is the one you bought.
• Direct wire, opposite ends: These tubes take direct 120-277V, but they want hot and neutral on opposite ends of the tube. They can be wired into any fluorescent fixture, and they are relatively safe. This is what you wanted.
• Direct wire, same end: These tubes take direct 120-277V, but one end is inert, and they take 120V and neutral on the two pins at the same end (yeah, 120V across those little pins? What could go wrong? LOL) These cannot work on instant-start fixtures, unless you also replace the tombstones, which is a stupid amount of parts-hunting and work. If you plug the tube in backwards it doesn't work, which leads to a lot of confusion during installation.
• Universal: These will both Plug-n-Play, and direct-wire-opposite-ends. They have better electronics so they can work both ways. This is what you thought you were buying.

As you can see, there's a lot to this.

Youtube sucks

The root of your problem is that you coasted on your assumptions and relied on a bunch of jackasses on Youtube. I realize many of us grew up with Walter Cronkite or Anderson Cooper being careful, reliable reporters of truth, so it's easy to get stuck on "Anything on TV is quality and well-researched". LOL not on Youtube.

Youtube is a sea of morons, and that's for a reason: Youtube is monetized. Content producers that get big enough can make 6-7 digits, get your gold Youtube plaque and quit your day job. Every starry-eyed jackass with a camera is rushing to turn their channel into that. They crank out lots of content in a big hurry, just to be first to a subject so they have more time to collect views and viewers, which is where the money is. They don't care if the information is accurate or thorough. They're not here to help you.

I don't exaggerate when I say "morons", that's part of the schtick: If you just try to do a straight informational channel with no jackass antics or clickbait thumbnails, you don't get views and it doesn't pay. There are much better videos that explain all of the above, but they don't get clicks so they don't rank so you didn't find them.

So enough with the Youtube.

The right way

Now that you know what to look for, you can take this back to the shop and find some opposite-end direct-wire (or universal) LED tubes.

Or you could go ahead and install a real T8 ballast and convert to real T8 fluorescent, which will be more straightforward. If your fixture has 1 wire going to each tombstone, get an instant-start T8 ballast. If 2 wires, get a rapid-start or programmed-start T8 ballast. Wire according to the instructions and diagram. Then you can use real fluorescents or the Plug-n-Play "tubes" you do have. The 90 CRI real fluorescent tubes on the market now are the best light made.