Hello Gilberto V.V. ,

As no one has so far made any recommendations so far- maybe someone will now see the post and be able to offer suggestions.

I have developed a PlugIn for my own use that can deal with this problem.
It's not signed by SDL as I don't wish to put my plugins on the SDL's AppStore,
and I only have this for SDL Trados Studio version 2017,
but I can make it available to you if you like.

SDL Trados Studio PlugIn - play with TM 2 (inconsistencies) [Updated]
https://deeptranslation.blogspot.com/2019/01/sdl-trados-studio-plugin-play-with-tm-2.html

D.O.G. Errorspy https://www.dog-gmbh.de/de/produkte/errorspy/ or Verfika https://e-verifika.com/ (both have trial versions) are useful QA tools that support TMX and have different advantages/drawbacks. Huge TMs can be a real issue with any tool (speed). One thing to watch out for is tools that alter the TMX (for example by deleting context information, invalid TMX etc.). I can't think of any QA tool that actually deals with minor linguistic differences in the source, only consistency checks that ignore tags similar to Heartsome.   Heartsome seems to do a pretty good job of not altering the TMX. Oh, and I think that https://www.rws.com/insights/rws-moravia-blog/how-to-clean-up-your-translation-memories-step-by-step-guide/# Phase 3 is a good recommendation for reducing the size of TMs to concentrate on more valuable TUs (chucking out old TUs with a usage count of 0 is a great way of slimming down a TM if you are feeling daring). Ultimately I would really love to see a better TM maintenance feature in Studio (that also allows you to see the context stored with TUs) and it does seem that work is being done in this area.

whatever you try, remember one thing

you are dealing with BIG animal(s)
so, speed matters, really matters
to catch up speed properly you have to handle it within its original tech - "SQLite",
not via extra export/import tedious time consuming steps
(for larger TMs, it usually takes hours and hours just import/export  while doing nothing useful). 
(recently, SDL made its TM size 3 times larger without any kind of evidence that its performance goes up 3 times, pity)

and, if you use "export/import" route, you have to remember one more thing
in the middle of that "converting" you could lose important information implicitly, that is very dangerous. 
-SDL's people say lots of times "Oh, that TM is corrupted" means.. that TM is garbage. That is not you wanted, I guess.

Yes, I couldn't agree more with the problems of importing and exporting which is all the more reason for having better TM maintenance tools in Studio. If you've found a good solution it would be useful to see your plugin in Studio 2019.

I have read your comment below carefully and visited all of the link you recommended.
That was good tip.

Regards

-ah.. there is no plan for me to handle SDL Trados Studio version 2019

I just discovered the SDL Translation Memory Management tool on the app store. It seems to remove true duplicate source segments (at least some of them) but not not inconsistent source segments. As such I couldn't recommend using this plugin at all.

that one use exporting/importing route, quite amazing..

I forgot Xbench from my list as it has a source QA check and handles sdltm. Suprisingly it was incredibly slow and just kept reloading the sdltm. Much faster with TMX though. The only problem with QA tools is they don't give you an easy option to review and delete what you find - which is exactly what your inconsistency plugin does however I am still unsure about whether it is wise to edit the sdltm directly like you do (excuse me for not knowing better but it just seems odd why SDL avoid doing this - I assume due to the complex database structure for context/fragments (upLIFT).

I do not know the true reason of SDL not doing so, I just think SDL is busy, super ultra buzy... I am a lazy one so I had no choice to make a tool of mine.