Selfhosted

https://discord.com/servers/8311-886329492438671420

Get rid of their junk equipment and put something decent in. Discord link is a group dedicated to doing just that. You may find info for your specific ISP.

If you do it right, you won't even need their gear inline at all.

Combination wifi & router devices are notoriously unstable. Those provided by ISPs are particularly bad. If you have the ability and the funds, spend a little more to get a prosumer router and wireless AP as separate devices that connect to your modem in bridge mode. In the long run, for me anyway, the stability and reliability of this kind of setup paid for itself quickly in less of my time wasted. My setup: my own cable modem per the specs my ISP provided, a unifi edge router X, and a unifi AP. I already had a server so I installed the AP management software on it, but unifi also sells a single board device to run that. Everything except the AP live in a little electronics cabinet tucked away. The AP gets it's power over Ethernet, so it can be mounted to a better placement with regard to walls, doors, pipes, etc. on a wall or ceiling with only a length of Ethernet cable running to the router. The AP itself just looks like a hand sized bump of white on the wall. I turned off the AP's status lights once it was setup so that it remains as discreet as possible. Adding a WiFi repeater from unifi nearer to the one room I still had a little trouble with was almost as easy as plugging it into the wall outlet.

Not everyone can or should go this route, and it was a learning experience for me with some growing pains, but in the end it was worth it to me. UniFi isn't the only game in town either. Either way separating your network devices so that each only does one job (the modem connects, the router routes, and the AP does wifi) means that one underpowered chip isn't being crushed under the weight of too many tasks at once.

Not every ISP allows this, but my ISP router is in Bridge mode and forwards all the traffic to my own wifi router. This means I get to place the thing and have full control over my wifi.

One thing you can try doing before throwing away the router (which is probably the exact same one your neighbor use) is checking the channel situation in your condo with an app like WiFiAnalyzer and also try moving the router around (some spots are better than others - and hi up is usually better)

That said, ISP routers are often terrible.

Update: they replaced a router with Huawei HG8145V5 and wifi was much much better, but freaking UI was supper laggy and I couodnt change some settings (like wifi channel) so I insisted on new one (again huawei) which finally arrived today. Getting almost full signal everywhere and 170/130 on speed test in the worst spot and UI is perfectly fine. Our walls and cabinet might be bad for wifi, but obviously ISP routers are just crap. I also found out bridge mode is not possible. Ill stick with this one for now, lets hope this serial number is lucky 😉

Thank you all for help

You can do a lot better by buying your own modem and router, but that can be expensive. The thing you're doing right now is a good idea if you don't want to spend a lot of money, whine at your internet provider and get them to send you a better router.