Is there anybody?

Continue with your use of the tongue, maybe invest in myofunctional therapy just to make sure that you're doing it right. Since you've got the resources for an ortho, look into:

1. The ALF appliance. Make sure to find a doctor who is good with it, and get it straight from the creator (Nordstrom) if you can

2. If you're in the UK perhaps visit Mike Mew. BioBloc appliance is his.

3. If you're elsewhere look into finding an LVI dentist who is up-to-date. Their methods are still being investigated by the users on this forum, but their ability to diagnose underdevelopment is sound. 

At 17 you'll see great results by fixing your tongue and body posture, but there are these devices and practitioners available if you feel that you need them. 

I live in Italy and it will be hard to find a competent dentist on this topic hahahah.

You recommend me the ALF appliance?

I recommend, above all, correction of the muscle posture. This will epigenetically correct your body/bones through correct stimulation and growth.

Yet I don't know how narrow/underdeveloped you may be. If you think that you are underdeveloped, and since you live in Italy, I would recommend the ALF appliance. Here's a directory for ALF providers who can be trusted to use the device properly:  https://alf.directory/  

Important to note: This appliance is very complicated to use properly, and not everyone who offers it is actually using the device properly. Now that you understand that orthodontists are blind on many of these issues, you know better than to just accept treatment from the first person who offers ALF. You owe it to yourself to educate yourself on the philosophy of how the device works/is adjusted, and then go to dentists and ask them questions to see whether or not they really understand what they are talking about.

Do you have any links or discussions on the forum about correction of the muscle posture?

thanks