I'll make a long story short, yes, this thing is super bad. I've had the same experience as you... Outside (on the balcony) I can easily get 5G and barely in the door 4G. I tested it at three different locations in Switzerland -> was always the same...

The locations were each +30km apart.

Basically, how good a connection is depends on other factors, such as the condition of the walls, the number of subscribers on the 5G mast and other interference factors. According to the manufacturer's specifications, it is a very good model for most Internet plans. According to the manufacturer:
- 5G performance: Up to 3.2 Gbit/s
- Network type 5G NR: n1/n3/n7/n8/n20/n28/n38/n40/n41/n71/n75/n77/n78
- WLAN standards 2412 MHz - 2462 MHz & 5180 MHz - 5240 MHz, 5250 MHz - 5350 MHz & 5470 MHz - 5580 MHz
- 2.4 GHz IEEE802.11b/g/n/ax 5GHz IEEE802.11a/n/ac/ax
- MIMO Dualband 2x2 MU-MIMO
- WLAN signal rate 3 Gbit/s - 573.5 Mbit/s at 2.4 GHz + 2402 Mbit/s at 5 GHz
- Transmission power CE: <20 dBm at 2.4 GHz
- CE: <23 dBm at 5 GHz