Best Way to Clone a Time Machine Drive

I am re-opening the discussion at Moving Time Machine backup to new drive - Apple Community

I recently moved a 2Tb backup to a 4Tb disk and find it surprising that Apple does not have really have a satisfactory solution. I read many blogs and reviews that say Finder is not a good method but after trying several alternatives, including Disk Utility, I have to agree that Finder is the best free solution for copying Time Machine disks.

It is annoying that it has a long 'preparation' step with no progress indication, after which user interaction is required; and it does not confirm when copy is complete (it just closes the window), but it does show progress when actually copying.

It is important to format the new Time Machine disk correctly first (to MacOS Extended (Journaled) because Finder will not warn you of a wrong format; you will only find out it does not work when you try to activate it in Time Machine.

Here is a summary of all my trials, all on MacOS Catalina on an iMac with 3.2MHz quad core i5 processor (nothing extraordinary). It took around 6 hours to copy 1Tb.

Carbon Copy Cloner           NOT SUITABLE       Refuses to copy Time Machine drive

ChronoSync  NOT SUITABLE       Looks like a good way of synchronising folders, but will not copy a disk

Disk Utility (MacOS) NOT SUITABLE       It said 'Backup disk not valid for restoring".

Do Your Clone          NOT FREE for cloning        Looks simple to use, but requires activiation to clone.

EaseUS Todo           NOT SUITABLE       Does backups, not cloning

Finder (MacOS)           OK. Apple-recommended method. Work but is not perfect.  Annoying 'preparation' step after which user interaction required before copying, but does copy reliably and gives progress bar with time estimated to complete. Does not confirm completiojn (progress bar disappears when finished).

Stellar Drive Clone   NOT SUITABLE       Will not run on a 64-bit machine!

SuperDuper  FAILED          Started OK but does not give estimated time remaining. Stopped part way for no apparent reason!.

True Image   NOT FREE for cloning        Cloning only available in the full version