That's honestly not a particularly intelligent question to ask, so I wouldn't say it's "better"...let me explain.
The Su-57, which couldn't benefit from one and a half decade of previous development and deployment of a indigenous stealth aircraft, took flight, completed an incredibly in-depth test program and has been deployed on combat missions successfully. It was a clean sheet, heavy, twin engine stealth fighter basically born out of the imagination and dreams of the engineers at UAC. It had a much harder time and succeeded regardless.
The LTS/T-75/Su-75, whatever you want to call it, starts from an infinitely more advantageous position. Not only is there now a considerable pool of knowledge and data related to the design, development, manufacturing, operation and deployment of stealth aircraft within UAC, the LTS is also a much simpler design and it can benefit from all the development work done for the Su-57 with regards to avionics, sensors, weapons and engines.
So no, the question not if it will fly, the actual question, which I already hinted at, is if it will be a successful aircraft or if it will fade into history as yet another prototype that flew a couple times and went nowhere. Like the MiG 1.44, or the YF-23, or X-32, you get the idea.