Hi and welcome! Well, that sounds a bit frightening. I'm sorry you have to worry about this situation for sure! I think you've been wise to see your doctors and neurologists and you've gotten multiple opinions, correct? That should be somewhat reassuring but it sounds like you still don't trust them. This article really talks about the difference between benign fasciculation syndrome and ALS. https://www.medicalnewstoday.com/articles/320388#overview It does state that the two can look similar so it is important for doctors to make sure of diagnosis. I have to believe your neurologist knows the importance of that. The article has a long section on causes of BFS that they suspect could contribute. Take a look and see if anything at all rings a bell. Anxiety and stress are on the list, by the way. Here is from the article that they do to rule out more serious disorders than BFS: they may also do neurological testing, blood work, and electromyography (EMG) to rule out nerve damage. BFS is not associated with nerve damage, so finding any nerve damage would be a sign of a different disorder. They also give a few easy things you can try although I will say in reading them, they probably won't soothe your mind on this. Things like taking up yoga and spending time with your pets. But also diet changes and lifestyle changes.
If you were my loved one, I'd say after the corona scare is not as prevalent, I'd schedule another appointment to discuss this. I'd go or the heavy testing this article suggests to be absolutely sure it is not ALS. Just for your peace of mind and because they CAN look so similar at the early stage of als. I would say too, go ahead and look into some of the things this article says you can do to self treat BFS to see if it improves things at all. Here's another article. https://www.healthline.com/health/benign-fasciculation-syndrome#treatment