They "deserve" whatever the market is willing to pay. Being the best at their sport doesn't mean anything unless you have a fanbase that wants to come watch you. We've already established that the WNBA fanbase is way below their expectations for what they are entitled to, and they are deluded. The top pro bowler doesn't make as much as NBA players either. There is little difference between the situation the top PBA players are in vs. the WNBA players...except the PBA players don't constantly whine about being underpaid and they have a much bigger viewing audience than the WNBA has. If they want more money, then get more fans to justify it.
As far as dressing sexy to make a living, you might want to ask Liz Cambage how she's doing with her OnlyFans account. She probably makes more money with that than she does with her WNBA salary, because apparently there's a bigger demand for her scantily clad pictures than there is for her performance as one of the best players in the WNBA.