As I understand it your outbound flight to DBV diverted to Split due to high/strong winds. You paid for a hotel and incurred costs to get from Split to DBV (most likely by taxi).
The return flight was cancelled as the incoming aircraft diverted to Zagreb (again due to winds at DBV) and you bought new ticket(s) with LH yourself. Wizz has agreed to reimburse these costs.

Both DBV and Split are notorius difficult airports to approach and if the pilots take the view that is is not safe to continue the approach/to land at DBV, you are really not in a position to question that. Are you expecting a judge or adjudicator to reach the conclusion that the pilots were wrong in their assessment of the situation in the air? The fact that apparently no other aircrafts diverted, is rather immaterial/will not have any weight. Hence, the diversion to Split caused by wind will most likely be considered as extraordinary circumstance and exempt Wizz from paying compensation. To the extent that the costs incurred (hotel and transportation to DBV) are reasonable such costs to be reimbursed; this has nothing to do with compensation for delay.

As for the cancellation of your return flight, this is a knock-on effect of the incoming aircraft being forced to divert to Zagreb due to weather. Again, you are really not in a position to dispute if such diversion is reasonable or not. Safety first!. Knock-on effects of weather or other extra ordinary circumstances will also exempt Wizz from paying compensation for the cancelled flight from DBV.

As for the settlement offer, you will not be able to accept the offer later if rejected, i.e. there is a chance that adjudicator will award you less than the settlement offer. If Wizz has acceped to reimburse your costs (this is the how I read the last part) and only the compensation for delay and cancellation is disputed now, there is a high risk that the adjudicator will side with Wizz. Nevertheless, if Wizz has accepted to reimburse costs, such costs should be reimbursed regardless if the adjudicator sides with Wizz on the compensation issues. It makes sense?