Kobe often appears surprisingly underwhelming in RAPM data - still very good, mind you, but lower than his reputation. This seems to be largely thanks to defence - he tends to peak as a small positive in certain small clusters, but his defence averages out to be a negative through RAPM (and this seems to hold in the playoffs, too, from what I've seen).
This is Engelmann's 15 year RAPM from 2001-2015, age adjusted (so Kobe's teenage years shouldn't really hold him back) -
https://docs.google.com/spreadsheets/d/1-R9RXLp6eYuRcptQIQVTBIkLrxvrTCfLh_WB2P-DBwE/edit?usp=sharingWhat is apparent, though, is that his DRAPM does seem to fluctuate quite a bit - after a good showing around 2010, it absolutely plummets from 2011-2013, and then Kobe gets injured (ergo, his post-2010 years may be somewhat overrated if RAPM is telling the truth). I do believe it was decently positive around 2000-2001 and 2008-2010, but craters at certain other times. This inconsistency could be influencing the results, or Kobe might just not be that good at defence on average, lol.
For a brief example as to how his 5 year clusters might look, there's a searchable table here -
https://www.thespax.com/nba/quantifying-the-nbas-greatest-five-year-peaks-since-1997/This doesn't split between offence and defence, but it's a good, quick source that contains
lots of 5-year stints, and it tells a similar story to what I've seen from Kobe in many other RAPM samples.
Shaq looks really good through RAPM - up until around 2005/2006, that is, at which point it drops off a lot. But prior to then, he's excellent, topping 1998's prior informed RAPM by quite a bit, and being the general 3rd guy to Duncan/Garnett in RAPM after that (and given that Shaq improved in the playoffs, it says positives about Shaq). The RAPM used to construct BPM 2.0 has 5 year splits, and Shaq rates excellently in 1997-01 (+7.7 - I believe he was the top ranked player to play all 5 seasons, but 4th overall), with his defence being only a slight positive (+0.6). 2002-06, his offence wasn't quite as gargantuan, although still great (+5.0), but his defence was a bit better (+1.0). His effort wasn't always there, but simply being a behemoth helps
Shaq looks clearly better from what I've generally seen through the RAPM scores, and it seems far more predicated on offence rather than defence.