Velop node not consistently connecting to best source

I recently moved into a new house and got the Velop mesh network to manage the WiFi here. In general it's great, but I'm having a little trouble getting consistent signal to my downstairs office, where my gaming PC is.

I have three devices in my mesh network: the Main Router, the node in my office (Office), and another node I've placed between them to help bounce the signal (Relay).

I set up Relay last night and saw in the LinkSys app that Office was, after a bit, properly connecting to Relay and getting a much better signal strength from it. My WiFi speeds immediately doubled.

However, this morning I see that Office has reconnected to the Main Router overnight, despite it being physically farther away and having a weaker signal.

Is there a way to force a node to connect to a specific node, or otherwise encourage them to stay linked? Nothing was physically moved, so I'm not necessarily looking forward to my internet speed halving or doubling based on vibes.