I'm not able to download apps on my iPhone 11 due to storage issues

Manage your storage space here:

How to check the storage on your iPhone and iPad - Apple Support

Start by deleting Photos/Videos, since that is likely the cause for most storage problems. You also have the option to use Optimized Storage to reduce storage on your device, but may need to purchase additional iCloud storage space to accommodate the data that will be stored there.

If you are unwilling to remove any data, then your only other option is to purchase a new phone that has more storage space. The storage space on your current iPhone cannot be updated.