Doorbell Continually Going Offline (Usually when requesting live view)

Hi, My Doorbell (Video doorbell 3) has started going offline frequently - several times a day. We've had for over 3 years and have 4 ring cameras in use too. It's been mostly fine... until the past few months when it's started going offline. It happens so regularly that it's rendering the device next-to-useless. I've seen a few other similar posts on here, but not found one that's resolved the problems we're having, hence this post. Sometimes it appears to be working fine. Still images appearing regularly, live view requests working instantly etc.... But very often I see that there's been no new still image for quite a while (all the other cameras show still images from seconds ago). Requesting a live view at this point normally fails. The app then shows the doorbell as being offline. When I've looked had a look, the doorbell itself is slowly flashing blue at this point (which I think means it's trying to connect to the network?) Eventually it comes back online. This can be after just a few minutes, or sometimes half-an-hour or so. It's connected to solar so the battery is usually 90%+. I've tried: *rebooting it *resetting it *changing the channels on my router in case there's interference. *Connecting to a different wifi network (I have 2 separate ones, and it doesn't say the signal is weak on either)rebooting the router and wifi networks. Nothing seems to fix it. All 4 stick up cameras work fine all the time, and they're split across both wifi networks. It's only the doorbell that is having issues. In fact, as one of the cameras is pointing towards the doorbell, I'm able to use the live view from that to see the doorbell flashing blue when offline, proving the network is ok. I'm beginning to think it's gone faulty, but don't want to get another if there's something else causing the problem. Is there anything else I can try to prove its healthy/faulty?