They are solving two different problems.

Arguments to its effectiveness aside, the current welfare systems seem to have the primary goal of providing for citizens until they can reenter the workforce.

UBI seems to have the primary goal of making sure people can maintain basic living standards when the jobs vanish. There will be a day when "just go flip burgers until something better comes along" will no longer be a valid retort.

If it checks the boxes in the name, not really.

Replacing welfare would still be welfare reform, but it wouldn't really resemble means tested welfare as we have it.