fortigate ipsec s2s VPN with starlink ?

hello every one .

recently we faced a problem with fortigate s2s with ADSL connections but , we solved it by changing PORT number and they are working great . thanks for all of you for helping .

the currrent config for SITE A and SITE B is as following :

site A: ADSL router ---> fortigate >vpn>IPSEC >site to site  > DDNS B >status : UP and can reach site B network

site B:ADSL router ---->fortigate >vpn>IPSEC >site to site   > DDNS A  >status : UP  and can reach site A network

Now , We are facing new problem which is  :

SITE A : As it is with above installation and configuration .

SITE B: changed from ADSL connection to star**bleep** connection and became lik this :

site B:Starlink router  ---->fortigate >vpn>IPSEC >site to site   > DDNS A  >status : Down Tunnel not Connected

.

i know there is NO port forwarding in starlink router and it is using CGNAT unlike ADSL .

i want to know how to solve this problem with the same configuration for both fortigate .

Do i need pfsens in site B to be in between :

Starlink--> pfsens ----(wireguard)---> fortigate -->etc ..

Or any another solutions ???

Thanks