Developer clearly stated that not all functions and features are yet present in A13.I would go back to A12 for the time being and wait for fully featured A13, which is basically just small update to A12 if we are to be perfectly honest
I always download the Gapps version of Arrow 13 and never have any problems. This way, I don't need to worry about what Gapps package to use.
Developer said yes, he always tries to make all updates dirty flashable, but I highly recommend doing clean flash when updating to higher versions of Android.
Same in A12.1
/* * We are not responsible for bricked devices, dead SD cards, * thermonuclear war, or you getting fired because the alarm app failed. Please * do some research if you have any concerns about features included in this ROM * before flashing it! YOU are choosing to make these modifications, and if * you point the finger at us for messing up your device, We will laugh at you. * It is your fault because you chose to do all the modifications on your device. * Remember projects like these and the work done on them is a hobby to the * contributors and the team members, no one is working for you nor is getting paid for it * have some respect for the work done by them since it is done purely on interest or a hobby */