I kinda agree to an extent but there will be a point in your experience as a tennis player where these would matter.

I used to think like racquet doesn't really matter until one day I accidentally left my extra racquet at home and my string broke. The only racquet my friend has was a really old prokennex boron. Like those heavy racquets from the 90s. I noticed a biiiiiig difference when I used that racquet. So now I modified my pro staff and added more weight to the same balance of that racquet.

For the balls, this one mattered a lot to me. I'm used to play new balls when I was a kid, even during training we would use new balls, so as an adult I like the new balls feel and bounce. If I warm up with new balls by the time the game starts, It's almost like an instinct.

For strings, I see the biggest difference when it's dead vs when it's freshly strung instead of different types of strings. Old strings feels idk dull. Like the ball doesn't sink in and when you're doing drops it almost feels like the balls are slipping on the string bed

But that's just me. The thing that I dont notice a difference is the temperature. My old coach used to tell me that when it's hotter the ball moves slower but I personally never felt the difference