I just had to go through renewing my residency in Spain. You need an appointment for every step. If you aren't able to check 50 times per day, you'll never succeed in finding an appointment. The process is completely broken. The only way to get an appointment is by paying a service to get one for you, which is between 50-100 euros. It is astounding that not only the process is so collapsed, but that the administration or foreigner police do nothing (they should just assign you an appointment after each step) to improve this. On top of that, they currently just legalized 500k-1million people who were not here legally, and I have no idea how they expect the majority (who are declared vulnerable) to be able to complete the immigration process.