UPnP and DLNA are a disaster of incompatibility and terrible usability. I've tried to use various UPnP/DLNA audio streaming hardware for almost 10 years and they have all had terrible issues. Most required the device controlling streaming to always be on, which is terrible for battery life and plain broken on tablets, etc. that go to sleep. Some only worked with Windows 7 media player's 'play to' command. I had to go through crazy setups like running multiple different UPnP services (bubble UPnP) just to make virtual UPnP devices that fixed bugs in my real UPnP devices, and even then things would mysteriously stop working.
Stay very, very far away from UPnP/DLNA. It's borderline false advertising IMHO to claim it streams music.
if you're using android, i suggest you try bubbleupnp https://play.google.com/store/apps/details?id=com.bubblesoft.... It doesn't seem to have the problems you describe, and it's also very happy to send stuff to a chromecast instead of a DLNA renderer. I could see how it's possible that your renderer is the cause of the problems, and that can be harder to replace since it's probably embedded in your TV (I've only used chromecast and samsung TVs).
I've actually had little to no trouble with DLNA overall, using among other things the ReadyDLNA server for a sparc readynas and rygel on ubuntu. i suppose it only takes one bad implementation among the components in your setup to ruin the whole experience, but i've been pleasantly surprised over the years how well it seems to work.
bubble doesn't have the best UI, but it's not bad, and there are other apps that are prettier (allcast comes to mind). in the past i would have totally agreed that most upnp controllers i had used had TERRIBLE usability, but most of those were embedded in A/V equipment (TVs, receivers), and what A/V equipment have you ever used with a good UI?
Stay very, very far away from UPnP/DLNA. It's borderline false advertising IMHO to claim it streams music.