It seems that, as soon as you transact with a sanctioned entity, you are globally in breach of the agreement and risking the revocation of all your certificates — also the ones for non-sanctioned countries.

Front matter:

   - it is called a "Subscriber Agreement" and not anything that suggests that its scope is a single certificate

   - it's a "contract [...] regarding Your [...] rights and duties relating to [...] Certificates" - plural

  - "[the agreement] will remain in force during the entire period during which *any* of Your Certificates are valid" - plural

  - "[by] requesting, accepting, or using *a* Let’s Encrypt Certificate" - plural