In practice, most businesses are simply handling this on a case-by-case basis since COVID is a temporary problem. Most home networks can handle the extra load as long as the employee makes sure that other latency-sensitive traffic, like gaming or video streaming, is kept to a minimum during the hours when they need to talk. If some home routers develop problems, IT staff simply build a queue and handle those one at a time. Sometimes they'll be able to access the router remotely with the employee's permission, sometimes they'll have to walk that employee through configuration steps to fix the problem. Sometimes the employee will just have to live with it unless the company springs for a new router or a higher bandwidth tier from the employee's ISP.
The VMO service worked well as a contact service for our class reunion. It worked as described and was a great resource for our classmates.

Holidays are often the busiest time of the year for any business — especially retail. Obvious, right? As obvious as that is, how confident are you, the exhausted employee or business manager, in your caller’s ability to recognize what exactly that means for you? Do you think they understand the torture of working long hours day after day and what effect that has on your mental and physical state? They might, but chances are they’re more concerned about receiving a personalized experience.
Don’t leave customers and colleagues on edge. If you say you’re going to call them back, follow up. If you tend to fall behind in this area, encourage them to email you or reach out in another way. Better yet, learn how to forward voicemail to email so you can access the message anywhere.