Skoda Kamiq Electrical Issues

That does sound like a low voltage problem. Given the symptoms you're describing and the mileage, the battery is a likely culprit. Have you checked the battery voltage with a multimeter? What readings are you getting when the car is off and when it's running? It could also be a problem with the charging system, so monitoring the battery voltage while the engine's running would also provide more insight.

I don't have a multimeter, unfortunately. But if the charging system was faulty, wouldn't the battery voltage drop while driving, causing more issues than just starting? Is there an easy way to check the charging system without special tools?

It's difficult to say for certain without proper testing, but the symptoms do point towards a battery or charging system fault. Even if the charging system is working intermittently, it can still lead to a discharged battery and the issues you're experiencing. Considering you don't have a multimeter, I'd recommend taking it to a workshop to get the battery health and charging system properly tested. They can quickly determine the root cause of the low voltage. It is possible that the battery is heavily discharged or defective.

Big thanks for the help! You were spot on. Took it to the shop, and it turned out the battery was toast. New battery fitted, and everything's working perfectly again. Cost me 290€, but at least the Kamiq is back on the road!