Around here we usually recommend doing the same rep range for your warmups as your working sets. So what you laid out sounds fine if your working sets after th 1@8 will be fives.
I’ve been using a warm up method that was given to me from my last coach from Calgary Barbell and I used the exact method for warm ups at my first meet.
Example: my last deadlift I hit a 365 single at RPE 8. My warm ups were as follows: 45X10, 135X5, 185X3, 225X2, 275X1, 315X1, 335X1.
If I’m feeling sore or stiffer than usual I might do an extra set at 135X5, or do 5 reps at 185 instead of 3. I’ve found this enables me to get warmed up and primed enough to get the top single of the day and not spend extra energy on unnecessary warm up sets.