I use heat shrink connectors on all of my wiring, any Auto Parts Store will have them.
https://www.amazon.com/Connectors-22-16-AWG-Waterproof-Electrical/dp/B0D5MF7735/?tag=jkforum-20
Do you still have the junk Factory battery clamps on? If so replace them with some HD clamps, also run a ground from the neg post to the alternator to give the engine better grounding.