Without answering your prime question … you are aware that Fairphone seem particularly sensitive to near full storage; it can result in fail to boot with no further warning soon after a “getting full warning”.
Settings > Storage … please take action on the phone if anywhere near full. ~85% is a compromise.
Both phones are syncing photos to murena.io. Stop sync was recently discussed in murenacloud threads. For example Help: DB Navigator & quit syncing murena workspace.