I'll start the discussion with this little tidbit from the help pages:
The workspace environment must be set before using several of the list functions, including ListDatasets, ListFeatureClasses, ListFiles, ListRasters, ListTables, and ListWorkspaces.
Your variables mentioned in lines will only return the path to each of the respective databases. Try it with a print() statement,
Given the limitation of the list functions, you want to work things a little differently in order to get what you want. Something like this might work for you: (completely untested: run it on some backup data first!)
import arcpy
featureGDB = r"D:\APRX_MXDS\USA_Parcels_2019_Project\Florida_Parcels_Per_County_Final.gdb"
tableGDB = r"D:\APRX_MXDS\USA_Parcels_2019_Project\Florida_Property_Data_Per_County.gdb"
arcpy.env.workspace = featureGDB
featureWS = featureGDB
featureList = arcpy.ListFeatureClasses()
arcpy.env.workspace = tableGDB
tableList = arcpy.ListTables()
tableWS= tableGDB
for table in tableList:
tableNum = table [3:-7]
for feature in featureList:
if feature == f'T{tableNum}':
inData = f'{featureWS}\\{feature}'
inField = 'the join field name in the feature class'
joinTable = f'{tableWS}\\{table}'
joinField = 'the join field name in the table'
arcpy.JoinField(inData, inField, joinTable, joinField)
This makes a couple of assumptions: the table names are just who you showed them and the feature class names are just how you showed them. It also assumes you want to join the table data into the appropriate feature class. According to to Join Field help doc this will be a permanent join to the feature class.
Hope this helps-
That should just about do it....