2018 Continental GT won’t start after sitting for a week – battery or parasitic drain?

So my 2018 Continental GT has been acting up lately. It starts fine if I drive it every day, but if it sits in the garage for more than 4 or 5 days, I come out to a completely dead battery. No lights left on, nothing obvious. I had the battery tested at a general garage and they said it was “weak” but couldn’t really tell me if it was the battery itself or something else draining it. I’m in Sharjah, and with the heat we get here, I know batteries don’t last as long, but I’m worried it might be a deeper electrical issue. I’ve read that Bentleys can have these parasitic draws from modules not going to sleep. I need to find a shop that really understands these cars and can do a proper diagnostic, not just throw a new battery in and hope for the best. Has anyone had a similar issue and found a reliable place that specializes in this kind of thing? I’m thinking I might need the Bentley battery specialists serving Industrial Area 11, Trusted and discreet, as I’ve seen a few places mentioned around there, but I’m not sure which one is actually good with the complex electronics.