Synology RT1900ac fell and still works, but has lost energy. Measure?

So this Synology RT1900ac fell to the floor and the cooling block has been clamped down with double cable ties acting as replacement for the plastic brackets that broke in the fall.

Everything does seem to work fine and in the same room I get around 30 MB/s coming in and 8 MB/s going out over Wi-Fi. At the moment I only have 2 antennas in as the third is getting glued.

However, the signal doesn’t get through walls very well, also not with 2.4 Ghz so I have to assume the level is low.

Any suggestions on how to measure signal strength and also what to measure on the motherboard to investigate better what’s going on with the signal strength? I don’t really have any good electronic measuring tools, so internal diagnostics would be nice. When I log in and look around the status looks good, but I’m not sure what to look for exactly.