what alternate to res.cookie() can i use to send token to the frontend?

Question

So ive been using res.cookie() to send the user's token to the frontend for a while, however, i've only ever tested it locally. I recently wanted to host my mern stack app on render.com and it turns out that i can't use res.cookie() to send the token to the frontend because cookies dont set within sub domains, which is what render.com gives you i.e "website-name.render.com". I would have to buy a custom domain name which i cant afford yet. This is what i mean

Sending the token to the frontend using res.cookie:

const register = async (req, res) => {
    const user = await User.create({...req.body})

    const token = user.createJWT()
    res.status(StatusCodes.CREATED).cookie('token', token).json({ name: user.name})
}

Getting the token using an auth middleware:

const authMiddleware = async (req, res, next) => {
    const {token} = req.cookies

    if(token){
        try{

            const {userId, name} = jwt.verify(token, process.env.JWT_SECRET)
            req.user = {userId, name}  
            next()
        }
        catch(error){
            throw new UnauthenticatedError('Authentication invalid')
        }
    }else{
        throw new UnauthenticatedError('no token')
    }

    
}

Essentially, this code above, which works fine locally, doesnt work when i host it on render.com, I am currently getting the "no token" error. Which brings me to my question, if i cant use cookies, whats my alternative here or am i forced to pay for a custom domain even though this is a personal project?