I tried asking ChatGPT 
for potential issues, providing it with the network inspect output, and one of the suggestions was:
5. Potential Issues with Parent Interface (wlxa86e84472f22)
The network is using the physical network interface wlxa86e84472f22 as the parent. This appears to be a wireless interface, and macvlan networks often have issues with wireless interfaces due to how they handle MAC addresses.
Wireless interfaces may reject packets from containers because they come with different MAC addresses than the host, which may cause network connectivity problems.
Fix: It's generally recommended to use a wired interface (e.g., eth0) as the parent interface for macvlan networks. If possible, switch to a wired network interface.
Has anybody experienced it before? Is it the TP-Link Archer T3U Plus wifi card which is a problem? Can it be somehow forced to work in that setup?
I really would like to use it as-is now, switching to the ethernet would be a real hassle for me - firstly, I’d need to buy a USB-eth interface, then to force one port on the router to use that subnet, and I don’t actually have any free ports even, so I’d probably need a switch, too 