Bringing Idrissa Gana Gueye back to Goodison Park is a smart move by Everton. Yes he's into his 30's now but it doesn't seem to matter these days. His style of midfield play is something Everton have needed - he can put his foot in, he can press, break things up and get things moving. That was the hallmark of his time at the club between 2016-19. Fans were sorry to see him go and he'll certainly be welcomed back.
And that's another good thing about this move. He knows the place, he knows the fans. He understands the club, and his settling-in period should be very short as a result.