A somewhat specific question on buying a power station in Europe

Quick background: I've just overhauled my van's interior from the previous owner and kept the plentiful electrics inside, only to discover (after completely rewiring and neatening everything and left for abroad) that my DC-DC converter isn't working. That rendered my batteries, solar, and inverter completely useless, and only by buying a regular car battery charger can I temporarily top them up once I find somewhere to plug in. Not ideal when working off grid was the main idea. I've seen battery power stations (the likes of Bluetti, DJI Power and Eco flow for example) advertised online for a while but with a few caveats that I wanted to ask you guys on opinions and possible workarounds.

Since I'm in Europe, nearly every electronics store has power stations advertised online but none available in store. The only way to get one is to have it delivered to a home address, specifically not a parcel locker, and driving 3-4 days to the in-laws (the closest deliverable address) isn't ideal since we see them in a month before heading straight back home after anyway. Picking up in-store doesn't seem like an option either, even Amazon won't do locker deliveries for them, my guess being the battery chemistry or their value.

Hence my reaching out here: has anyone had success in finding a battery power station in-store, or having one delivered to a parcel locker in the Alps region (France, Switzerland, Italy, Austria) since that's where I currently am? It doesn't need to be a particularly large one either, the 200-400Wh capacity ones are enough for my needs which are on the smaller/more compact sides. I've mostly looked at MediaWorld, Euronics, Decathlon, and a couple hardware and electronics shops.

Appreciate any leads and thanks in advance if you can help!