Mac OS Mojave 10.14 was released in 2018, as a result it has finished security updates quite sometime ago. Due to this release has not been patched for security for quite sometime now it maybe quite vulnerable to use. Presently Mac OS Big Sur, Monterey, Ventura and Sonoma are presently receiving security updates. Therefore I would recommend updating to one of these releases for optimal protection against known threats and vulnerabilities. As Mac OS Sonoma has just been released this may result in end of security patches/updates for Big Sur, so maybe update to Monterey, Ventura or Sonoma just to be safe.