Should I open up a second retirement account or open a brokerage account

I’m 23 living at home with my parents so I’m pretty much just pocketing everything I can get from working. I already have a 401k Roth I opened up maybe 2-2.5 years ago and it has 46k worth in it. I have my saved money wrapped up in a CD constantly. I have an acorns account opened up just because I like having a little piggy bank that I can just forget about. I was going to start investing some money into a brokerage account somewhere and hopefully one day have something 15-20 years down the road if something really bad happens. Some people tell me it’s a better idea to open up a traditional retirement account somewhere else, but I’m sort of looking at it like I want an investment that I can use later if I genuinely need without a penalty and I don’t know if I should be looking at it that way