Search by custom user property?

The docs say we can add custom properties to a user, like so:

    Sentry.setUser({
        id: user.id,
        companyId: user.company.id,
    })

This works fine insofar as I can see the companyId in ‘user data’ against an issue. Is it not possible to search/filter by these custom fields though? I haven’t had any success yet…

It feels like I might be better off adding the companyId as a tag?

I usually go with a tag If data has some value when used with Discover, like SetTag(“user.companyId” = …)