Wow. I've never used Gandi but I have seen it recommended before as a low-cost option. I will actively encourage people to avoid it from now on. That's scary.
High to extreme higher end would be something like MarkMonitor.
Gandi might be better than some of the other low touch, self service domain providers but its definitely still in the same ballpark. $18/year still means they're losing money if they ever need to pick up the phone for you. It's not a price point that works with "higher end".
They used to be very good if you wanted a non-scammy registrar with a huge selection of TLDs and ccTLDs. However, in recent years, success seems to have gone to their head and the service is nothing like it used to be (plus their latest control panel UX is an abomination).
Feels like the CEO has made his money, forgotten the company's roots in the process and is happy for Gandi to be just another generic, overpriced registrar running on auto-pilot.