Acquiring magical artifacts can be difficult, but keeping them can also be so ;) But there are a few things that can be done here:
1) The hunters are trying to kidnap you using a standard abduction scheme, meaning protection from hostile schemes is key. You must have a good (loyal!) spy master (with a designated task to protect against schemes), activate the appropriate countermeasures. Check if your marshal can reduce the chance of hostile schemes (sometimes he has such a task) and also assign appropriate tasks in your court, in particular hire loyal bodyguards. Schemes usually need agents to succeed, so if vassals and people in your court like you, this will also increase your resistance to kidnappings/murders. Also use decisions to fight schemes, if you can uncover any.
There are also magical ways to increase protection. The Orb of Truth can reveal schemes. Bonuses from certain demons can either indirectly or directly increase resistance to schemes - Nyx can also reveal them, as can the Orb.
2) It may also be worth trying to reduce the number of hunters in your area, as they tend to initiate schemes or join in as agents. If you find out that a character has a witch hunter secret (or trait), it's best to eliminate/imprison such a character.
3) But you can also approach the problem from another angle. Why are hunters so interested in you? Perhaps you have revealed yourself as a witch (you have a witch trait instead of a witch secret)? Or perhaps you are abusing black magic/eating kids/murdering prisoners with Darkblade?
If you practise magic in secret, avoid suspicious activity, and don't carelessly cast spells, the hunters may focus on someone else.
4) Alternatively, you can set Hunter Activity to low in the game rules, this will also solve the problem.

ah okay i understand. This makes sense, if its a standard kidnapping scheme. Ill try to get my defenses higher.
But truth be told, it would be better for the gameplay if i could at least retain my claims on these artefcats they stole from me. Else its too big of a hassle tbh

Yes, the kidnapping and witch trial is very punishing when it comes to artifacts. If you survive (sometimes it happens), you keep claims. Otherwise you have to start from scratch, although at least you know where the artifacts are.