Both are great options in this price range. But I recommend you to Go for Redmi Note 7.
| Redmi Note 7 | Redmi Y3 |
Display | 6.3 | 6.26 |
Resolution | 1080x2340 | 720x1520 |
| USB C | Micro USB |
Body | Aluminum
Glass | Plastic |
Pixel
Density | 409dpi | 269dpi |
Front
Camera | 13MP | 32MP |
Rear
Camera | 12MP | 12MP |
Processor | SD660 | SD632 |
Processor
Speed | 2.2GHz | 1.8GHz |
GPU | Adreno
512 | Adreno
506 |
Other Camera specs are Identical in both devices. Both have 3.5mm Jack, 4000 mAh battery, IPS Display, same aperture size of camera and both come with Android 9 Pie.
Only in front camera Redmi Y3 leads but still you get a lot more in Redmi Note 7.