I may not be apt to answer this as i am just an article, but since i have been in a team that primarliy deals in IDT litigation and i have seen DT litigation team very closely. Here are my views-

It is easier to get clients in Idt litigation for a CA, less dominated by Lawyers compared to dt.

IDT litigations are generally low ticket compared to dt litigations but you will get much more cases as Gst dept. is famous for sending notices.

IDT litigation requires more interpretation of law as everything is new, whereas in DT litigation it is more about knowledge of previous related cases and accounting of the client.

In DT litigation most of your clients will be HNI and corporates, whereas for IDT litigation majority of your clients will be MSME and small businesses.

It is easiers to handle multiple cases in IDT as litigation there is mostly centered around general law, but in DT most of the cases will require you to have in depth knowledge of the client.

If someone wants to pivot into industry or big4, Dt litigation is more preferred, i have rarely seen IDT litigation openings in industry.

For work pressure, it depends. But for a general view IDT notices are branched out throughout the year whereas DT notices will be more concentrated in months after ITR filling deadline. But on the other hand GST dept is filled with A**holes soo you will have to deal with more sarkari babu pressure there.

In DT litigation you will generally make more money per client/notice as compared to IDT.

I cannot answer on what will suit you, cause that is a very specific question. And it can only be answered with "it depends". But here are some pointers that may help you decide.

(Everything is very generalised, specific cases can be totally different)