It is NOT a roll-up window shade style as the Golf Wagens come with. My 2019 e-Golf has a rigid parcel shelf that mounts behind the rear seat. It is stowable under the rear cargo floor, if you wanted to remove it. If the previous owner disposed of it and it is no longer with the used car: I have seen GTI/Golf-R owners who have been willing to part with that part separately. You just have to watch for someone parting a car with an internal combustion engine. It's the same parcel shelf between the gasoline and the EV versions. It takes 6 seconds to install it.
If it suits your needs, as a commuter car. I'd say go for it. I love mine, and I have only racked up 5,500 miles in 15 months. Even my wife loves ours, and I was skeptical how well she'd convert to liking an EV being that she's driven a VW TDI for 14 years.
Wheels are entirely changeable, but most larger diameter, wider width, less "
pizza pan" looking wheels come with a range penalty. I charge once or twice a week, so range penalty means little to me. Here are my range penalties (205-50-R17 Continental PureContacts on 17x7.5" Audi A3 wheels):
Be warned, if you live where there is a season called winter, EV's come with a range penalty in winter, especially if you want cabin heat. I live where it's summer year round. I think I've had occasion to use the seat heaters under 5 times.
On your question of used vehicle pricing: As VW was closing out this model (2019), deals were available on them NEW for incredible pricing at some dealerships. The incredible pricing came with an added potential savings due to the IRS EV Tax Credit, in addition to any state and local incentives. All I received was the federal tax credit, but it was totally worth my while to acquire a commuter vehicle that never needs gas while VW was offering heavy incentives to push these cars off the lots. Do I wish it had more range: Sure, but we still have two TDI's if I need to drive hundreds of miles without stopping.