If money isn't an issue, or you can find a good used one (next to impossible in the current climate though), the HK P2000 with flat base plates is near identical in size to your P239 with 13+1 rds of 9mm instead of 8+1 rds. Both the mag release and slide release are ambi.
Guns don't kill people. Apes with guns kill people! - Robin Williams
Number of handguns currently owned and previously owned: 45.