does Apple Watch stay charged more than 1 day

It depends on your usage and the watch model you purchase.

Apple Watch SE and Series 8 are rated for UP TO 18 hours per day.

Apple Watch Ultra is rated for up to 36 hours

Your mileage may vary depending on what you do on your watch.

Have you checked your battery health on your watch? Since it's a 6 and you've likely owned it a couple years at least, its battery health has to have declined (which is what batteries do). On your Apple Watch, open the Settings App and then scan down to Battery > Battery Health. It most assuredly has declined as it should have by now. And when Battery Health declines, which is normal, the battery cannot hold the same amount of charge it did when new. Still, if you're getting up to 24 hours, you're doing great, since the watch is specked to provide up to 18 hours in a day.