By sheer coincidence, I think I solved this problem on my new Huawei only this afternoon (if it is the same problem).
I got separated from my group and finished ahead of them.
To pass the time while waiting for them I persevered with this problem on Wikiloc. I know its a different app but I think the same fix applies to Viewranger. The problem lies with Huawei's phone settings, not the app.
Here's how I fixed it on Wikiloc:
Click profile
click settings
click advanced settings
click "Troubleshoot recording problems"
click Battery optimisation (I'm not sure of the exact route into this as my phone now has the problem fixed and may be throwing up a slightly different menu)
Scroll down to Wikiloc and change to "Not allowed" i.e. don't allow battery optimisation for Wikiloc as it curtails how often the location finder searches for a signal.
While there I also disallowed battery optimisation on Viewranger.
Caveat. I don't know yet if this solves the problem. Have to wait until I bring the dog for a walk tomorrow.
Might try that. Although I'm passing the phone to my wife and getting another Samsung instead.
I lost my Samsung a few weeks ago and felt exactly as you do. Now I'm not so sure. The Huawei is slooowley growing on me.