This maybe the unpopular opinion, but Endgame Thanos >>>> IW Thanos BUT both were effective for the tones of the movies
Thor decapitated the infinity war thanos. That version was more so remorseful, honorable and seasoned. With the stones, he was on God level but he knows that there was a heavy toll that came with that level of power. Also by having the stones, he didnt have to fight anymore, and didnt even use armor. Eventually the bill came due for him.
Endgame Thanos from 2014 was more of a ruthless warrior that was slightly younger, strategic and quite frankly, did not give a fuck. The fact that he sat there and watched his own decapitation from the future and not have an ounce of emotion about it, only saying "thats destiny fulfilled" made him more terrifying.  He didnt want half of the universe gone... that nigga said fuck EVERYBODY, fuck a 50% I want 100%. That nigga BOMBED...damn near NUKED the entire compound, without a question asked, then sat in the middle of the crater he left for the avenges like Cell and waited for them. SAVAGE LIFE.
If you ask me he was lowkey better without the stones, he still WORKED Thor, Steve, Tony, and even Carol.