I noticed recently that the wrath keep attacking the summoned mob from the iron spell mod despite not doing any damage. From short research what causing the problem I come to an issue on the iron spell github and see that they are not using the NBT {Owner:} but rather "summoner". So I think that the wraith is attacking mobs that not have NBT {Owner:} although they are have same player tag or I'm wrong.

I currently use simplyskills-1.7.1+1.20.1.jar & irons_spellbooks-1.20.1-3.4.0.jar

If you think this is not Simply Skill problem I will close the issue and post over their repo.

iron's Spells 'n Spellbooks mod is a forge mod, how can I run it together with Simply Skills mod which is a fabric mod?

iron's Spells 'n Spellbooks mod is a forge mod, how can I run it together with Simply Skills mod which is a fabric mod?

Use 3 mod together:
Forgified Fabric API
Sinytra Connector
Connector Extras

Use Sinytra Connector by Su5eD. On curseforge page the mod will have link to other 2 mod