I think we're way early to have clinical evidence for a lot of vagal nerve theory that is approachable by anyone outside research fields, but I've had my eyes opened to how much is connected to vagal nerve stimulation (VNS).
For example, basically deep belly breathing reduces stress supposedly through VNS: https://pmc.ncbi.nlm.nih.gov/articles/PMC6189422/. Yoga, yes, but also even popular and known in some military and police cultures where I've seen it labeled "tactical breathing" as a proven way to lower stress responses like heart rates on command. There seems to be growing evidence around some of these responses being real and reproducible.
FWIW, I've personally observed this working in my family with a licensed therapist as a family member was able to develop and rely on belly breathing to interrupt the onset of panic attacks. There's a lot of talk - if not reproducible science yet - about the possibilities of positively outcomes through so much connected to the vagal nerve.
At something more of a stretch, the same pro-VNS therapist posited to me that even swallowing is a way to engage in VNS, and thus might have a connection to eating disorders. Sure enough, maybe there is emerging evidence: https://pmc.ncbi.nlm.nih.gov/articles/PMC8027699/
Emerging therapies seem to always get a sideways glance from the medical industry which loves its double-blind derived protocols, so I've started to be more receptive to being part of the vanguard in experimentation when I or someone I love is acutely suffering and it doesn't have a known protocol to alleviate it. An example of that reluctance in PTSD, of course, is the controversial psychedelic therapies: https://pubmed.ncbi.nlm.nih.gov/38284341/. Sometimes these treatments just need time, and if they're reproducible, they grow in popularity.