Loose slide? 620 rounds?
Frankly, I have two PARAS in open IPSC rig in 38 super, two p16-40s,half a dozen p14-45s,etc,etc..you get the picture.
I really like Paras.. In IPSA.[the hot dogs favor STE mostly.]
I shot NRA for years decades ago, and there, play in the gun was best at a minimum it was thought.
Tight in battery is most important to accuracy.
My old gold-cup is loose as a goose, and I use it for IDPA, as it eats any kind of ammo..it has many thousand rounds through it.
Now, in the new close range sports, [idpa-ipsc-steel challenge, etc.], reliability is most important.
So, as so well put above, my not so humble opinion is: If it shoots , shoot it. A lot.... Stop worrying.
If the play really bothers you that much, put the slide in a vise and squeeze it.