Thanks @Kevin_Z . Leaves me with a router that has issues :-( Any other suggestion besides bringing it in for repair?

@Kevin_Z The positive part is that the WiFi stays okay on the previous firmware. As for your question, I'm not sure if the wired connections were still working. Did not actively tested those. So,...

I recently updated the firmware on my router from 1.2.5 Build 20190411 rel.52981 to the latest version available on the site: ArcherC5400(EU)_V2_210308. This version is not found by the internal...