I have the same install as you, and i booted into Windows and left my PC for a while, I came back as it went to sleep. I saw the network adapter reenable itself as I logged in, and still was unable to reproduce your described behaviour with fluxer. If this is only an issue with the desktop app then its some local DNS or other related problem.
I'd be interested to see if Electron could be configured to use a DoH fallback in this situation to see if it fixes it
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Comment by @omstr