Signal sensitivity very poor

Hello, I'm not sure whether related with the major upgrade released some days ago, but I noticed that my Nokia X20 signal reception is dramatically low. If I stay in a place with a strong network coverage, like outdoor in a typical urban environment, it works perfectly. But, if I just move a little in a place where the signal is not simply perfect, than there is no signal at all - not even to allow calls. I see the typical icon of "no signal", it doesn't matter whether I keep the network type automatic or if I force it to 2G, 3G, 4G or 5G. This happens with with both sim slots (even using one of them only - no change at all in the behavior), and with multiple operators. Of course, the same sim cards showing this issue with my X20, are working perfectly with other phones (even Nokia).

I really can't say whether this issue has been raised after the upgrade since my phone is brand new, and I used it only a few days before the upgrade. And those days I was using it at home, where the signal coverage is super great - thus I couldn't detect any anomaly.

Anyone else with the same issue? I think I'll have to return it for repair... :-(