I generally just solder two LED strips together, though I realize there are clips/clamps that will do the same thing, I never seem to have them when I need them. I created this jig to make it easier to solder 2 10mm LED strips together. I also, somewhat reluctantly, created one that you can put short 22 gauge wires in between the LED light strips. Make sure to peel enough insulation off the ends or it will burn and stick to the jig. These jigs need to be printed in PETG at the least as the soldering iron comes in close proximity. Even then, plan to print one every once in a while, fortunately, they are small and print in 11 minutes on my PS1. On the plate in the .3MF there is the default for wires, and one for slightly smaller wires.

I have another variant of this I published a while ago.

10mm LED Strip Soldering Jig by Jeff Smith - MakerWorld

While it should work with just about any 10mm LED, I use https://amzn.to/3oHOXkx