is making a 5th gen fighter thats a stealth fight but how stealth on planes work is to have a low radar cross section so a radar cant see you but as for the su 5 has quite a large cross section also not to mention the plane is held to gether with wooden screws
a VTOL plane in landing or takeoff mode is more like a helicopter than like a fixed-wing aircraft, so the pilot has to essentially master two very different aircraft with completely different flight characteristics in order to fly one airplane
now saying that the vtol on the f 35 is only used for the navy variant for obvious reasons while russias main plain the su-57 is in a much worse spot then americas highley advanced f-22 and 35s an such the point the russians were trying to make with the su 57