I know that you can sort layers in the table of contents, but this approach doesn't sort tables. I have lots of standalone tables, and if they get knocked out of order for any reason, it is very time consuming to drag and drop to reorder them. The following script seems to do the trick, and sorts all standalone tables in a new group in the TOC. I'm posting here to help anyone who has a similar problem, and to see if anyone else has a better approach.
# get active map in current project
p = arcpy.mp.ArcGISProject("CURRENT")
m = p.activeMap
# sort table names
sortedtables = sorted([t.name for t in m.listTables()])
# create new group
g = m.createGroupLayer("Sorted Tables")
# for each table, add to group and remove the original
for x in sortedtables:
t = m.listTables(x)[0]
m.addTableToGroup(g,t)
m.removeTable(t)