ronto:
I am a S&W guy all the way, but the Ruger LCR has a relatively light DA trigger--though its trigger pull L-O-N-G relative to the S&W J-frames. Feels like they made that trade-off deliberately. The LCR is light and will have more recoil than the SP101.
The SP101 has a gawdawful trigger pull and reset, IME.
Smith & Wesson K-frame and L-frame DA trigger can be tuned to be very light. And used & inexpensive K-frame .38spl (+P if you want) M10 and M64 revolvers are just a smidge larger than your SP101. If you want .357mag, it will cost a few more $$$.
If you are open to semi-autos, but still want a longer DA-ish trigger pull that happens to be light, the striker-fired pistols are an option. Glock, S&W M&P, etc. Used Glocks are cheap, though more in .40S&W than 9mm than in years past. Not to my taste, but hey are reliable options.