Firefox, probably others are complaining of:
Cookie ‘exp_last_visit’ will be soon rejected because it has the “SameSite” attribute set to “None” or an invalid value, without the “secure” attribute. To know more about the “SameSite“ attribute, read https://developer.mozilla.org/docs/Web/HTTP/Headers/Set-Cookie/SameSite
Is there a way to set this within EE as I cannot find any reference to it.
yes. this was a config override that was recently added: https://docs.expressionengine.com/latest/general/system-configuration-overrides.html#cookie_samesite