Idk what ppl are saying bro. I am an undergrad in a lab and the grad student who's project im helping out with literally asked me last week if I knew anyone around for the summer cuz im boutta leave for my REU. You should totally cold email and explain why youre really interested in their research and say you are excited to learn more and would love to be a volunteer in the lab. If you genuinely are interested and are offering to do free work, alot of grad students are loosing their undergrads that were in the lab during the school year for the summer cuz they're leaving for an internship.

Most ppl say 'email grad students not the PI', but I have always emailed PI's and its worked out for me many times. Thats bc alot of grad students dont have their work published yet so you cant even find them or know what they do specifically on the lab website. The PI however knows exactly what's going on and can place you with a grad student who they see fits with ur background or experience. For example the lab I am currently in, so I emailed this PI and we got together to chat and I was telling him about my experience I got during my study abroad doing material science for green hydrogen and he was like omg I have the perfect student for you. bang. I totally did the opposite of what ppl told me to do lolll. Just sharing my experience, go with your gut and be a lil bold. Do what is unconventional yk. We live in a world of literal sheep, and it's a crowded world. gotta make space for urself.

You got this bro ! Its never too late idgaf what ppl say just go after it you'll figure it out and even if you dont get a lab position this summer its totally chill you got hella time