You might have some success with this approach if your ISP can’t give you a static ip.
It’s very common with fibre connections because the world is clinging to ipv4 and there are not enough addresses available given the format of ipv4. Ultimately ipv6 will solve these problems but it requires more investment in coding so guess what, few are bothering.
I think it’s interesting that most of us domestic fibre customers have not noticed what we’re being sold is not what we previously had. It’s like getting veneered instead of solid wood!