First off, rebooting everything didn't help unfortunately. I'm able to play Tidal via desktop app and mobile apps w/o no issues. Just seems to be the Mu-So. And it's been fine ever since the last major firmware update that fixed the original Tidal drop-out issues. Outside of the usual Android app updates, not much has changed. I did switch from 200Mbps Xfinity internet to ATT fiber internet a few months back, but again, the Tidal issue just started today.
Network-wise, my home has ethernet ports in most rooms. The fiber modem is connected to the main router (Asus RT-AC88U) that does all the DHCP, port forwarding, DDNS, etc.), and the ethernet cables leading to each room are plugged into that router.
I have a 2nd Asus RT-AC68U router in my room running in AP mode and several devices (including the Mu-So) are connected to it. That router is connected to the wall ethernet port. TLDR; the Mu-So is hard-wired to the LAN. 2nd router is there to just ensure there's high bandwidth AC signal throughout the house and has the same SSID. Not sure if all that is relevant, but that is the setup (excluding some additional gigabit switches in various rooms).