OP I think you need to push back, politely (in this case), explaining that the ACTUAL problem is not the address, but the drivers ignoring your specified safe place with a neighbour who works from home and has agreed to take them in, and therefore you'd like to make a counter complaint because you are being disadvantaged by the driver's actions ie this sounds like a problem driver on your route not following both instructions and common sense, as in full view and presumably also out in the rain is obviously not an acceptable place to leave them and not what you have asked for.
(There is also a small chance that the driver is stealing them but I wouldn't say this in your communications - once an actual human looks into this they might see a pattern on this route should that be the case.)
I do think you should have tackled this when parcels started to go missing, but other than that I don't think the PPs criticising you are being reasonable, I think we all know that delivery drivers often don't follow delivery instructions and leave things in stupid places that they actually aren't meant to at all! We used to have this with Yodel at a previous address, and also have a problem now with one regular purchase that is sold via Amazon but dispatched from manufacturer using DPD. Our local DPD 'service' is a pain in the backside, and also inconsistent, so for this item I think we are going to have to use a locker.
While your issue gets resolved, I also think you should pause your ordering so you don't get blacklisted, or tweak your ordering to get more things into less deliveries and a specific delivery date when you will be there. Also agree with regard to asking the neighbour to use their address for a bit, but as a neighbour I'd be okay with this 1-2 times a fortnight, I wouldn't if it was almost daily. Using their address a few times would be interesting, because if they leave parcels on the neighbour's doorstep when the neighbour is in, it proves your driver is an idiot who probably isn't bothering with safe spaces, ringing doorbells, etc.
I don't really understand what the big problem is with ordering for a day you are not at work though? Almost all of my Amazon orders come 1-2 days later, on the day specified when I order, using Prime. Are you ordering lots of niche items from sellers using the regular post that don't fit through your letterbox? Maybe you need to stop this.