Oneplus companie’s successor of Oneplus 5 named Oneplus 5t is the best phone that you can buy below 40000.
It offers 8/6 GB RAM variant with 64/128 GB ROM. Its battery lasts really long.And the camera performance is one of the best. Its unbelievable to get a flagship in this rate. my cousin has took it. There are more things to explore in it. It has a great vibrant display. I also thought about buying this phone, but my choice is Google Pixel 2. If I had another choice I would have bought it. I suggest you to buy this phone, if you need a flagship and the budget is low.
It will not make you regret. Thank you!