I usually play chess at chess.com but recently i downloaded lichess and there i defeated 1700 players effortlessly, and I am 1300 on chess.com, There is a huge difference between ratings of chess.com and lichess.
so what do you think which one should be given more priority? or which one is better?
Neither. Different rating systems. Different player pools. I do think lichess has less volatility in their ratings, though I have no statistical proof. In other words, when I play a 1700 player, he feels like a 1700. On this site, players feel around plus or minus 300 of their actual ratings. That’s at my rating. Ratings may get less volatile at the higher ratings.
As for the ratings: there is no absolute best rating. Statements like "i defeated 1700 players" are meaningless without specifying the place where you did it. The places have different communities and rating systems