Even in the Chrome hegemony you don't want to be missing Edge and many others, so you test chromium.
Similarly, while not perfect you can test WebKit, and if you like, on Linux or Windows, for example:
https://orionbrowser.com/platforms/linux
Apple wouldn't be in the business of VMs with Safari, but if you're looking for MacOS VMs, turn to a CSP: https://aws.amazon.com/ec2/instance-types/mac/
Many have software testing orchestration pre-wired.