For what it's worth, codex doesn't yet seem to be aggressively terminating accounts or invalidating auth tokens if they detect usage in a non-first party tool. Whether that will continue to be the case or not a gamble though.
Try opencode go using kimi - its more than enough for most usecases unless you try something really stupid that you shouldn't be getting openclaw to do directly, like coding.
Z.ai explicitly allows you to use it with OpenClaw on their plans.