95 e320 no power

[BC in the Bay]

I'm having a weird power situation and I can't seem to find a similar post anywhere. I had an issue with starts getting progressively more strained over a couple of weeks and then nothing. I replaced the battery and the alternator and after putting the new alternator in, the (new) battery died while the car sat for a couple of days. I took the battery in for testing, they said it was dead and gave me a replacement. I put the new battery in, got the car to start and ran the engine for a 10 minutes or so in the driveway and then left it for about a week.

When I went to drive the car on Monday, it was dead again. No power to the locks, or instrument panel when the key is inserted. I took the battery out, charged it overnight last night and put it back in today with the intention of finding a vampire somewhere, assuming that I had something draining the battery. The battery measures 12V, so I think it's ok, but I'm still getting no power at all. I'm getting 0 amps when measuring from the negative terminal to the (disconnected) battery wire. I also tried a tester light and am getting no light.

I checked all of the fuses in the box and the ones by the battery. This seems like a blown fuse somewhere, but I can't find any information on what to check here.

I'm sure this is something stupid that I'm missing - anyone have any ideas?