Heritage reviews the data on allegations of widespread lines and racial differences in wait times:

There were reports on Election Day of long lines in some isolated
locations around the country. But the average wait time in America was
only 14 minutes. Some have also erroneously claimed that there was some
kind of discrimination at play because the average wait times for blacks
was seven minutes longer than for whites. But blacks tend to be
concentrated in large urban areas and, according to the MIT study, the
most populous areas had longer wait times than those living in areas
with fewer voters. Even The New York Times was forced to admit that the “lines were longest in cities.”

Those large urban areas are almost exclusively under the control of
the President’s own party, whose local officials make the decisions
about precinct size, voting equipment, and the number of poll workers.