Summary
Joe was the #49 pick in the 2020 draft, and is known for being a shooter. After struggling to get any real minutes during his first two seasons in Philadelphia, Joe was picked up by Oklahoma City and has played really well for the Thunder, including hitting over 41% from three on high volume and being a regular part of the rotation. He even ended up starting some playoff games over Josh Giddey.

Joe probably needs to continue to hit above 40% if he's going to make an impact in the NBA, but he has started to show signs of expanding his game. While his assist rate is tiny, Joe can hit some shots off-the-dribble, and he has been showing real improvement in that area over the last couple seasons. At 6'4" and very thin, Joe will likely struggle defending bigger wings unless he is able to put on some weight. However, he gives good effort and overall has been able to contribute to a successful Thunder defense.

If Joe can continue to be an elite shooter, he'll be able to stick around in the league, and could even become someone that is a regular starter on good teams. He has yet to turn 25 years old, so there's reasonable hope for continued growth in his game.
 
Cap Considerations
Joe has a $2.2 million team option for 2024-2025, and if that is declined he will be an unrestricted free agent with a $2.1 million cap hold and Early Bird rights. Using his Early Bird Rights, the Thunder could offer him a starting salary of around $13 million, which should be enough to retain him. However, that likely wouldn't even be an issue considering if they want to retain him and he plays well enough to warrant that kind of money, they can just exercise the option.

There is a scenario, like what the Pelicans did with Herb Jones, where the Thunder could decline his option to re-sign him and lock him down early. Since the Thunder are fairly cheap now and could get expensive later, they may try to go down this route, especially if they can give Joe a front-loaded contract. Another benefit of this option is that Joe would have a very low cap hold, so the Thunder could still maximize their cap space while locking Joe down long term.

At this point, if the Thunder decline Joe's option it would only be to re-sign him on a long-term deal, so there's really not a scenario where he is a free agent that is available to other teams in 2024.