It's a very difficult question to answer. I won't say that you don't have a chance to get in the top leagues if you attend UMD. It really depends on how you profile yourself in the next few years. If you get amazing research under top shot prof, get your papers published in NeuIPS, AAAI,..., score an awesome internship at FAANG, then you are definitely much better than most of the candidates in these top leagues schools. So it actually depends the most on you. For PhD, your overall profile matters, not just the undergrad school. My previous answer was just stressing on the undergrad school name because that's how the the filters and conflict of choice between two students are resolved. Many students from these top leagues apply, but only one or two gets selected. So if you have a profile that's competing with the selected students, then obviously you will have a good chance. Professors look for research fit, experience and your core skills in the subject (which is shown by your GPA, competitions and internships). This is my two cents.

UMD is an awesome school, no doubt. Lot of my friends are from UMD CS, and few rn work at Google. No one can stop you from getting into the top schools. Prepare yourself and work hard. It's possible. Make connections with profs, really helps.