You may need to check whether the public ip is reachable first from the internet.

Normally ISP now implement CGNAT or carrier grade network address translation.

Means you cannot do a ipsec site to site vpn if either of your line is behind a ISP CGNAT.

https://maxis-fibre.blogspot.com/2016/06/ma...address-vs.html
https://soyacincau.com/2021/10/13/tm-unifi-...implementation/

Do check this first.

If you believe you have been assigned a public static ip address, this type of ISP package is normally more expensive.

You need to test it first with any of the web tools against the ports that is opened via port forwarding like
maybe https://fqdn

Then if it doesn't work. Reach out to Maxis via twitter or social media or email tech support.

All the best