First of all, Welcome to the forum! I hope we can help you.
IRN, Alex and Lord Derbyans are all intense chewers. As you go up in size you will need a steady stream of wood chews. The larger the bird the more expensive these toys will end up being. There are affordable options, like natural branches if you have trusted forests in your area that you can confirm don't use pesticides.
The size of the cage is another consideration. Lord Derbyans and Alex will need a similar sized enclosure. The Alex has a very long tail. Lord Derbyans are much larger birds by weight= more food and more toys. I am bring this up mainly because budget was part of what you shared as a consideration for one of these birds. All of the species will need fresh veggies and some fruit also which can get expensive over the course of a year depending on what your budget is. Keep in mind this toy, veggie, fruit and veterinarian annual budget will be for the next 30 years or more.
Derbyan Parakeets or Derbyan Parrots | Beauty of Birds
Derbyan Parakeet (Psittacula derbiana) | Parrot Encyclopedia
Alexandrine Parakeet (Psittacula eupatria) | Parrot Encyclopedia
In terms of behaviour the Asiatic parrots are not physical birds in the way your GCC was. So be honest about this consideration. If you want a bird that you can scritch and physically interact with an Asiatic parrot may not be the bird for you. Asiatics love spending time with their people and they are HIGHLY intelligent. I find my plumhead very rewarding. They just show affection differently. Their feathers aren't like other parrots and they don't need help with pin feathers. Generally they can be overly stimulated by touch and can either nip or get sexually aroused. Most only get physical for copulation.
Feet are a safe touch area. Step up is no problem
If you are coming from a GCC who was all about scritches it might be an adjustment for you. May I asked what happened to your GCC? How old was your little one? It is so hard to say good bye