Cache/buffer (again)

I've been streaming with the ATEM Mini Pro for a few years without issues, but the last month has had a series of failed streams due to the cache filling up. Things to know:

• I normally stream at 3 Mb/sec, but I went down as low as 1 today without making a dent in the cache. My internet speedtest (done during immediately after the service) says I can upload at 9 Mb/sec, and nothing else uses this network during the church service. I don't think the issue is too much traffic.
• I typically stream to Restream, but today I also tried streaming directly to YouTube RTMP. The result was the same: Cache fills up within a minute or so, and the video is completely unwatchable after that.
• At one point two weeks ago I discovered that my YouTube stream had been set to low latency. I turned it to normal latency last week, and the cache problem wasn't there that week. I don't even know if that is part of the problem or not. Regardless, I set it at normal this week, and the cache problem returned.
• My ATEM Mini Pro is unplugged from power when it's not in use. The only times it is in use are Sunday mornings from roughly 9AM until noon.

I'm almost to the point where I'm going to give up on streaming altogether if I can't get this resolved. It's not worth the headache I go through every week to make this happen. Any advice would be greatly appreciated, mostly for the sake of my sanity.

Good afternoon BTPERKINS, did you ever get this resolved? I am having the exact same issue, and it's quite frustrating