Have you tried any of the Bluetooth or USB hardware adapters for SEGA Dreamcast? If you don't like the official nor unofficial controllers for DC, then just get one of these like the USB4Maple bus adapter and utilize your favorite USB controller or one of the other ones for Bluetooth.

For example, like the SEGA Genesis or Saturn games / sequels that arrived on the Dreamcast via official or unofficial means? Then use a modern official SEGA Genesis controller with a wired USB cable or USB wireless dongle and play that way! Prefer the wired controller for PS3, Xboxes, Nintendo Switch, or the like? They are now an option! Want to utilize the Wii Remote or another Bluetooth compatible controller? Go that route!

Whether they are PC or console controllers, if they are Bluetooth or USB and they aren't trying something too weird nor proprietary, then they should work with these modern, fan-created adapters for Dreamcast!

I haven't tried any of them yet. However, I have heard good things about them and their hardware compatibility. Please let us know if you have tried or will be trying any of these!