It sounds like your domain name entered the redemption period. The high fee to restore a domain in the redemption period is mandated by the registry, not the registrar. So Gandi is not price gouging; they are required to collect that fee for restoring the domain.
Once you renew the domain, there is an immediate 60-day (?) period when you cannot transfer the domain elsewhere. So you’d have to wait for that duration and then transfer. You won’t lose out on the expiration date though.
When you transfer the domain to another registrar, you’d have to pay a one year renewal fee, which will extend the ownership of your domain by one more year than what it was before.
Contrary to the other reply, I do NOT recommend calling and doing it over the phone, as in my opinion that will just be slower and prone to accidents by adding a human into an otherwise automated process.
The process is free as in gandi won’t charge you to migrate but newer registar might , and also if you DNS or other services the new service provider will likely charge for those.
[1] for .come .net .org and many other popular ones it is, however for some of newer Top level domains (TLD) they may have only one domain registrar and you cannot move. .dev is owned and operated by google alone.
Gandi afaik does not have exclusive access to any significant TLD so it shouldn’t be a problem
The new registrar will charge a fee and the expiration date of your domain will increase by one year. The transfer fee should be roughly the same as the registration and renewal fees. If anything looks fishy, compare with another registrar (starting with common registrar recommendations you see at HN)