Looks every bit his 35 years of age??? what games are you watching, he's just played 40 games for us in a season, been our best outfield player, and gets about the pitch just as easily as he did 5-10 years ago.
His game doesn't even rely on pace. Even if he did slow down it wouldn't be affecting him too much.
The greater risk is not giving gana gueye a 2 year deal, its spending 40m on a instant replacement because you would struggle to get someone of his quality ready made.
Give him a new deal, sign a young player who has similar traits, that we can spend a season or two polishing up and getting ready for the PL as his replacement, like a club with brains would do.