Does undergraduate course load matter in graduate admissions? So I get that most people take 100% course load which for my school is 5 courses a semester, I know some people take lower course load and only take 4 courses per semester but end up taking 5 years in total to get their degree as opposed to 4.

My question is does someone who take 5 years to complete undergrad studies(because of lower course load) at any disadvantages to someone who took 4 years to complete their undergrad? Graduate admission for example, does it look bad if you took more than 4 years to get your degree?
It's fine to spread things out a bit.  You might consider taking a gen ed requirement over the winter term, and some summer classes, to avoid extending things too much.

Taking a reasonable credit load per semester shows maturity.  It also helps prevent burnout.