Incorrect RX and TX on the Wan interface - Archer C7


I've got OpenWRT 23.05.2 on an Archer C7 v5 (setup as a router, dhcp, ap) as well as the same version on WR1043ND v2 (setup as a dumb ap). They are working flawless the last month or so.

Couple days ago I started setting up Home Assistant and I thought about adding some data from OpenWRT. Using the UPnP/IGD integration in Home Assistant, I am able to get data such as WAN Status, WAN IP, Download Speed, Upload Speed, Data Received, Data Sent.

All great until I wanted to convert the sent/received data (B, assuming bytes) to something larger and easier to read like Gigabytes etc. I noticed it was way too low to be true. I checked the luci interface and it reports also unrealistically low values on all interfaces, including the WAN interface. I've been downloading tens of gigabyes of data from external sources as a client through this router the entire day, and it still says only 9.82 GB on the TX for WAN and 350 MB for RX (that's another thing, isn't WAN supposed to log it as received under RX and not on TX if the data is even a little to be believed?). The same thing with Download Speed and Upload Speed - now, I don't know where Home Assistant is getting the download and upload speeds from on OpenWRT since when I go to real time graphs in luci, the readings in real time are appearing correct with what I'm doing with my clients.

I'm coming from DD-WRT where they had monitoring for these things in line with my expectations, so I am a little confused here.

So the obvious question is, am I misunderstanding the TX and RX on the WAN interface in OpenWRT or are the reported values actually wrong? Also, what are some suggestions to work around this, if there are any workarounds?

Thank you in advance!