Bam is incredibly powerful as you would expect from the main character of a long running series. He would give many fighters a good battle but that’s not going to be the case with Jiren. Jiren’s abilities are absolutely crazy to the point where his barrier may be able to repel all of Bam’s attacks. Even Goku was unable to breach that barrier for a long time. Jiren won’t even need to get serious this time. Jiren wins.