There's another question called Why didn't Doctor Strange use the Time Stone to prevent Thanos from claiming other Infinity Stones?.
This question is totally unrelated and was thought up before I have ever read that other question.
I understand that using the Time Stone can lead to negative effects. I also understand that you can still use it. For example, Doctor Strange uses the Time Stone to age and un-age an apple in Doctor Strange.
So, why doesn't Doctor Strange use the Time Stone to age and un-age Thanos in Avengers: Infinity War? The two consequences
Thanos is un-aged and is now Baby Thanos. I am sure Baby Thanos is much weaker and easier to defeat than Super-Strong, Muscular, Adult Thanos. The gauntlet cannot even fit on the hand of Baby Thanos! Then, Baby Thanos would be unable to harness the power of any super-powerful and mighty Stone. This consequence is beneficial for the Avengers.
Thanos is aged and is now Elder Thanos. I am sure Elder Thanos is much weaker and easier to defeat than Super-Strong, Muscular, Adult Thanos. Age Elder Thanos enough and you get Dead Thanos. (Mr. Thanos can die of old age, right? Even if that age is really, really large.) Dead Thanos cannot fight the Avengers! And he surely cannot kill half the people in the universe. This consequence is also beneficial for the Avengers.
So then, why not use the Time Stone on Thanos?
Here is an analogy. Refer to it in your answer.
The Time Stone is the same thing as an "I Win" button. If I use the Time Stone, I press the "I Win" button and ... I win! If I do not use the Time Stone, I do not press the "I Win" button and I have to spend extra effort making sure every little detail of the complex plan works exactly the way I planned it - which is much harder, much more random, and much less guaranteed. Why not take the easy way out and press the "I Win" button? Win guaranteed. 100%.
In other words, I cannot see what can go wrong. Your answer can tell me what can/will go wrong or any problems with my assumptions. For example, I assume Thanos can be aged and un-aged. If this is not possible, support this argument in your answer.
Another thing to address. I do not want your answer to simply say "Well, Doctor Strange found a method that worked. Why complicate a plan by trying something that might not work." Show me that my plan might/will not work. Also, don't tell me there is only ONE case where the Avengers can win (which is what we see in Avengers: Infinity War). I know this is not true. Given that there are literally an infinite number of "branches" that occur when searching through the future, really, Dr. Strange was extremely lucky to find a winning future in just 14 million searches. There is more than one winning future.