Some POET products seem tamper proof due to the advantages of the interposer manufacturing process, and this integrity may become a vital selling point. My guess is Chinese 5G products may be restricted to domestic use only. Theoretically those types of components might be permitted to trade from Singapore.
In a recent article about China's tampering with server products assembled by Supermicro, it wasn't any particular sub-components that were compromised. Spying hardware was snuck in at the assembly stage at the end of the supply chain. I really doubt anyone could compromise a POET component, but as to whether an assembled product that uses a POET component can be so compromised, that will depend on the ability of the team running the assembly factories at every stage of the supply chain to have the wherewithall to resist the tactics the Chinese have already successfully used at Supermicro.