Summary
After entering the league as a wing, Crowder has had success the past several seasons as a small ball four (in today's NBA we can probably even just remove the "small ball" from that title) in Utah, Memphis, Miami, Phoenix, and now Milwaukee. While he plays his "3-and-D" role well, his mostly lost season in '22-'23 (he sat out in Phoenix waiting to be traded, and got little playing time after being traded to Milwaukee) brings into question if he is still a starting-level player.

Offensively, Crowder is mostly just a spot-up threat, as the majority of his attempts come from 3-point range (about 60% of his attempts over the past three seasons). He's a career 35% 3-point shooter, and has hit around that mark over the past few seasons. You'd like to see him hit at a slightly higher rate, especially since he mostly shoots pretty wide open attempts, but he's good enough to be a credible threat.

Crowder may not be an All-Defense level player, but he can hold his own against elite wings. He has the size and strength to guard bigger wings. Even at age 33, he still moves his feet pretty well and can stay in front of his opponent in on-ball situations. He has consistently put up good steal rates throughout his career, and his 2.2% steal rate in '21-'22 was in the 91st percentile for his position, according to Cleaning the Glass. He contributed to some successful Suns defenses recently, which finished 6th and 3rd in defensive rating in '20-'21 and '21-'22, respectively.

Age-related regression might hurt Crowder as he enters his mid-30s, but as long as he continues to hit shots he'll continue to be a reliable role player. He plays hard and makes the right plays on both ends of the court.
 
Cap Considerations
Crowder will be an unrestricted free agent with a $2.1 million cap hold and full Bird Rights, so the Bucks will have no restrictions on re-signing him.

Other teams will have multiple ways to sign Crowder as even teams without cap space could possibly use any of the Non-Taxpayer MLE, Room MLE, or maybe even the Taxpayer MLE or Bi-Annual Exception to sign him. It's also likely that Crowder only gets minimum offers, and he may not even get fully-guaranteed offers.