To add to this very fine write-up (sorry OP... nice effort, but this will go unseen or ignored by most of the sub and you will still have to deal with a bunch of posts wondering what the hell is going on with Capela):
We are going to re-sign Capela to a multi-year contract. This is a given. The FO has acknowledged his worth and we have no alternative available in our system or FA next year that offsets the financial costs of paying him. The whole reason we let Ariza walk is because we have already blocked a huge salary for Clint into our budget.
We are going to get a good deal on that contract (assuming you judge Clint as basically a max-level player). Clint loves playing here and unless I'm mistaken, is totally fine with his role on the team... There has been no smoke about him demanding more touches or even playing time, he seems to get along exceedingly well with James, and he even spends his time doing things for our PR staff like Fashion Copela. He does not want to go anywhere else. He knows our system is good for him and our success will help him get paid.
But sure, he wishes he could have secured a bigger contract this year (bad luck for him and all the other RFAs). However after watching the DMo and Noel situations go down, he surely understands that locking in a decent chunk of change is the top priority.
As long as we don't low-ball him with something like a final offer of 4yr/60M (I'll admit I thought this was on the low end of his possible range - before his stock-raising playoff run), he should not hesitate to sign on.
Players like Adams and Gobert make about $23M/yr and play more minutes than Clint, so I think it is safe to call that the upper end of a potential "market level" deal.
The max offer he could have received from another team this season was $27M, iirc.
If we offer him $21M/yr (Same contract fellow RFA Aaron Gordon signed), he would have to leave over $16M on the table for next season by taking the QO... That is a HUGE risk to take after watching DMo and Noel strike out so badly doing the same strategy. Especially since the $21M/yr contract is only $24M total away from his possible max... Why would anyone give up a guaranteed $84 million over the next 4 years to play this season for $5M and take a chance at maybe getting paid slightly more per year on his next contract?