Trump did close the border to illegal aliens.
To get the flood of illegals flowing again, Biden-Harris:
Suspended the remain in Mexico policy
Stopped construction of the border wall, and sold the remaining components
Lifted the title-two restrictions that turned back unaccompanied minors
Canceled the expedited removal program
Reversed refugee bans from key regions
Enabled flights from those regions to begin
You've been told this any number of times, yet you keep pretending you have not.
You support mass migration, yes?