Yeah I was gonna suggest sewing in straps of a big piece of velcro. Also look at Viola cases or similar, sound's daft but look a lot less conspicuous.
https://www.ebay.co.uk/itm/112198017963?_skw=violoin+soft+case&itmmeta=01JEGEM97337JT76TGJEC0S1M0&hash=item1a1f85e3ab:g:jAQAAOSwZqZaK90d&itmprp=enc%3AAQAJAAAA8HoV3kP08IDx%2BKZ9MfhVJKkrdC0CSRhkgAP7l%2B%2BilyqcATmhqQzXrsD9l8sRKuR4gNwLt9kLa9lCafnBXszIjXit4bAsdgSQG8FcuRSO%2FUomdD7%2B5oBbCBR4B2IkuMJJeROUAm4HtH1YB7GvKytgcTaqjZ8GIqDNhPIUCZf2BaEngpfO9NumwE5E7Roaj9VGCDkO3aYnDYjEyzn%2BaQAeW1QO9%2FHTveZzxS4LAF8j3gyphj4Kjm%2B37DCi476sNmB4Rc0uiojjVUyx8ot0N378JcCdVj6WofszUNYIudA4u47udfMmz653C6ORB%2FuvdcXtFA%3D%3D|tkp%3ABk9SR9iT0Y70ZA