Veteran 4xTBS players probably know the cheesy tech trade strategy. If you don't know I will explain.
Trade every 1-3 turns and look for technology you don't have. Acquire that technology and then trade it to everyone else for profit.
While this becomes very tedious, you will have all the latest techs, be the richest person in the galaxy by far, and never have to worry about money again.
This makes the game insanely easy.
Now here's some synergies to make the strategy even more powerful-
Get everything you can to increase you diplomacy skill.
Never trade diplomacy techs to anyone.
Contact everyone as early as you can.
Only research what the AI doesn't. (the AI is predictable on what they research)(you can also not trade what you research to get way ahead in tech)
Be forewarned, if you use this strategy, the game will become so easy that you will probably lose interest in it. Not to mention it's very annoying having to micro so many trade deals so often.
Possible fixes for this exploit-
Trading techs can only be done with a trade tech treaty, which would require very good relations.
Option to disable tech trading.
Everyone may only trade techs they have researched