This is what Biden said, per factcheck.org:
"On the day the White House announced the travel restrictions, Biden did say at a
campaign event in Iowa that as the pandemic unfolds, Americans “need to have a president who they can trust what he says about it, that he is going to act rationally about it.” He added, “This is no time for Donald Trump’s record of hysteria and xenophobia – hysterical xenophobia – and fearmongering to lead the way instead of science.”"
At no point did he say (1) he disagreed with the travel ban, or (2) that the travel ban was itself xenophobic.