Welcome to the forums, newcomer!
I would say that you're overthinking this since an SLI setup doesn't net any benefit other than it being a room heater and asking more power from your PSU, not to mention demand the right lanes from your motherboard.
Before we go any further, mind sharing your current specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
How old is your PSU?