MySQL Workbench shows running query but query not in process list, eventually times out at 7200 seconds - insert

Question

Purpose: Remove duplicate records from large table.
My Process:
Create table 2 with 9 fields. No indexes. Same data_types per field as Table 1.
insert 9 fields, all records into table 2 from existing table 1
Table 1 contains 71+ Million rows and 232 columns and many duplicate records.
No joins. No Where Clause.
Table 1 contains several indexes.
8 fields are required to get unique records.
I'm trying to set up a process to de-dup large tables, using dense_rank partitioning to identify the most recently entered duplicate. Thus, those 8 required fields from Table 1 plus the auto-increment from Table 1 are loaded into Table 2.
Version: 10.5.17 MariaDB
The next steps would be:
Create new Table 3 identical to table 1 but with no indexes.
Load all data from Table 1 into Table 3, joining Table 1 to Table 2 on the auto-increment fields, where table 2.Dense_Rank field value = 1. This inserts ~17 Million unique records
Drop any existing Foreign_Keys related to Table 1
Truncate Table 1
Insert all records from Table 3 into Table 1
Nullify columns in related tables where the foreign key values in Table 1 no longer exist
re-create Foreign Keys that had been dropped.
Creating a test instance of an existing system I accomplish everything I need to once - only the first time. But If I then drop table 2 before refreshing Table 1 as outlined immediately above, re-create and try to reload, workbench shows query running until 7200 second timeout.
While the insert into Table 2 query is running, opening a second instance of Workbench and selecting count of records in table 2 after 15 minutes gives me the 71+ Million records I'm looking for, but Workbench continues running until timeout.
The query shows up in Show Processlist for those 15 minutes, but disappears around the 15 minute mark - presumably once all records are loaded.
I have tried running with timeouts set to 0 as well as 86,400 seconds, indicating no read timeout and 24 hours timeout, respectively, but query still times out at 7200.0xx seconds, or 2 hours, every time.
The exact error message I get is: Error Code: 2013. Lost connection to MySQL server during query 7200.125 sec
I have tried running the insert statement with COMMIT and without.
This is being done in a Test Instance set up for this development where I am the only user, and only a single table is in use during the insert process.
Finding one idea on line I ran the following suggested query to identify locked tables but got the error message that the table does not exist:
SELECT TRX_ID, TRX_REQUESTED_LOCK_ID, TRX_MYSQL_THREAD_ID, TRX_QUERY
FROM INNODB_TRX
and, of course, with only a single table being called by a single user in the system nothing should be locked.
As noted above I can fulfill the entire process a single time but, when trying to run up to the point of stopping just before truncating Table 1 so I can start over, I am consistently unable to succeed. Table 2 never gets released after being loaded again.
The reason it is important for me test a second iteration is that once this process is successful it will be applied to several database instances that were not just set up for the purpose of testing this process, and if this only works on a newly created database instance that has had no other processing performed it may not be dependable.