Not much you can do.
Some people may not care and are ready to get back to the office. Working from home can be worse for some, than working from the office.
Make sure your staff know the numbers when it comes to covid 19. It's not as dire for younger people than headlines make it seem.
From
US CDC Age Range
18-29 - Cases
5,882,115, Deaths 2,318 CFR of 0.04%
30-39 - Cases
4,294,281, Deaths 5,458 CFR of 0.13%
40-49 - Cases
3,885,505, Deaths 13,511 CFR of 0.35%
Females are much less likely to die than men as well. You can also assume the US a little less healthy than Thailand at least as far as BMI goes, so that should reduce those CFRs.
Those who self identify as "high risk" health problems or immunocompromised should be provided with the ability to be secluded or work from home still. Those who live with elderly parents is another factor. Your staff most likely won't have a problem, but transmission to others they live with could be.
Make sure the office is well ventilated (windows open for breeze). People are spaced appropriately. Masks when required in close proximity or meetings. Or better yet, distance & outdoor meetings. Could stagger days or hours as well to reduce how many people at a time.
Ideally those who are willing should get vaccinated as soon as possible. Maybe buzzwoo could help facilitate that through education about how to get that done.
Temperature checks upon entry and making sure anyone who feels mildly ill should stay home until they get better.
I'm not a medical doctor so don't take any of my advice and please do your own research, but supplementing with vitamin D to make sure staff is not deficient seems to reduce transmission and severity of covid. Computer screen rays are not the same as sun rays.
Ivermectin is available over the counter in Thailand (hard to find & sold out, but available) and may or may not reduce transmission of covid-19 until vaccination. Again DYOR (actually read the full studies though, not the headlines). Goes by the name Vermectin in Thailand available in 6mg pill at 100 THB a pop.