Computer questions you'd be embarrassed to ask any where else!

You can check the system locale (the region and country) this way:

https://www.tenforums.com/tutorials/132050-change-system-locale-windows-10-a.html

https://learn.microsoft.com/en-us/answers/questions/2327599/how-to-change-system-locale-in-windows-10-the-lang

Beyond that, it's most likely a browser cookie problem or an issue with the setup of FB itself.

To change the language in FB:

https://www.facebook.com/help/327850733950290/

Or clear the cookies in your browser (best google the method for your specific browser).

Hope it helps.

Solid stone walls are challenging for any sort of wifi setup.

Ideally run ethernet cable (cat 5e/ cat6) into each room where you want reception, then put a wifi access point in each room.

Ethernet cable is only about 6mm diameter and not that difficult to run through walls etc, suitable long drill bits and indeed SDS drills to do it are widely available and cheap, I did this myself.

Mesh is really only worthwhile when the points have wired access back to your router

Wireless "repeaters", or any wireless so-called "mesh" an ISP might sell you, is basically worthless. They work - up to a point - but will halve the wifi speed on your network, at best. They'll struggle though heavy masonry walls and ruin the wireless speed of the rest of your network while they're doing it.

I'll offer another perspective on this having fitted a mesh system to a solid wall house recently. As I mentioned I used the Deco system and distributed two of the nodes around the centre of the house and another (which becomes the main unit) at the router located at one of the walls. The mesh then connects from the main unit to the remote ones - either directly or by hopping off one to get to the other (you'll see the structure in the app).

There may be a slight drop in absolute performance on a high-performance network, yes, but at the end of the day the system is more than capable of running all of the TikTok and YouTube streams that looksee needs 😆 without flapping.

Note above I mentioned that I fitted the remote Deco units to the centre of the house and not into the extremes where there is no coverage - that's the mistake that many make - they put the remote units into the far-off room and wonder why it won't talk to its friends. Put it half-way and let it extend the coverage. Another trick might be to place one of the remote units into a window bay which overlooks the problematic area.

Now, if cables can be run to two of the Deco's, then by all means do it (you then have a wired 'back-haul' or connection to the main unit, rather than another WiFi link), but if you follow my logic above then the Deco will sort itself out in the majority of installations.

For the 180 EUR it cost for the x50 or the 130 for the M4, it's a very good solution.

Ah yeah, all depends on the house, but it might be sufficient to for many to use.

I try to avoid unless you can test a set for a while first to see how reliable they are. As you say depends on house wiring. Even newer houses have trouble with spikes killing the link. Only solution it to turn off and on the affected plug to re-establish connection. Its something tp-link etc. have not been able to fix properly as far as I know…