I think the most reasonable arguments have him between 8-14.
The easiest way to boost someone or tumble them down the rankings, while making a pseudo reasonable argument, is to highly value old school guys or current players who are near the end of their careers. So if you really want to tumble Kobe (or any player) do both!
Here's my method for getting Kobe down to the low 20s.
0. Assume the top 10 is any order of Kareem, Russell, MJ, Lebron, Bird, Magic, Hakeem, Shaq, Duncan, Wilt.
1. I have Kobe in a tier of "cuspy top 10 guys" with Jerry West, Big O, KG, Dirk, Dr. J, David Robinson. So let's start by ranking all those guys ahead of him, lowering Kobe's ceiling to 15ish.
2. Let's now put Curry, Chris Paul, and Durant over him. Heck let's throw Giannis in there and go crazy.
3. Now let's roll in some old school guys that are impossible to compare to Kobe: Mikan, Elgin Baylor? Moses? should I go wild and say Bob Pettit?! (no jamaalstar, that would be too powerful.)
4. Kobe is now in a tier with guys like Nash, Wade, Karl Malone, Barkley, Harden, Stockton, Pippen. I can't justify putting him at the bottom of this, but I can make a arguable case for a few of these guys (some peaked higher, some played in less desirable circumstances etc.). So I'll put Kobe somewhere in the middle.
There you have it, an easy recipe for Kobe as being ranked the 21st-26th-ish player of all-time.
- Use old school bias and current player bias at the same time.
- Put players in tiers and then bump the subject player down to the bottom of the tier. Do that twice

I don't personally condone doing this though, unless you're a hater trying to add some plausible deniability to you Kobe hater analysis. You can do this for any ATG by the way.