Reusable foodwares are completely safe under proper hygiene protocols, even during covid.
Please see a factsheet created by Unwrapped Project about COVID-19 and reusables. See more here.
The health section of the Canada Reduces website also have more on this topic.
In June 2022, over 125 health experts vouchsafed safety of reusables at the height of COVID-19 pandemic witnessing the alarming amount of disposables used and tossed away during the pandemic.
Laws of California and Canadian provinces allow BYO practice not just at food vendors and restaurants, but also at grocery store delis.
Bottom line: it is safe, even during the pandemic, under proper hygiene protocols.