I would say like all sports boxing has evolved a lot over time. The training methods, nutrition, PEDs, etc are all way better nowadays so it's unfair to compare.Lewis is one of the goats for sure. I would like to see how he would fare with the best boxing fighters from the 70s though.
All combat athletes, soccer players, basketball players, etc would get destroyed by fighters from the current era.
I'd be curious how he fares vs Fury or Wilder because fighters from the 70s I'm quite sure would be punching bags for him.
Boxing in particular I think guys like Ali and Tyson get overrated due to their personality while a guy like Lennox enters on reggae music, drinks tea and stay out of trouble outside of the ring so he gets overlooked easier.