The worry with AR is that he won’t be as good on another team. Think Jordan Poole after the Warriors.
Larry Bird I believe it was famously said he wouldn’t sign players after they were on LeBron’s team because LeBron makes everyone else better than they are. This could be the case with AR. If so, the Lakers need to trade him this year because once LeBron goes, AR may lose his trade value.
There is a chance that Reaves will leave the Lakers in the next offseason anyway, as he has a player option for next season in his contract. Personally, I think that he will be looking for a big contract in the next offseason and may well move to another team, especially if the Lakers' offer to extend his contract seems insufficient to him.