CvC

If you go to https://support-portal.plarium.com/en/vikings-web/faq/clans-battle/competition-features

you will see how CvC pairs are formed based on influence and checkpoints passed in last CvC

You do not give much information but perhaps you did well in your previous CvC and your clan is very large, this gives the system much fewer choices for pairs.

On the other hand if you are small and your opponent was from a newish kingdom, they could still be growing quickly and perhaps building/ upgrading a Stronghold just before CvC starts due to inexperience.

Or as Turbomaster74 said new members could have joined after CvC was announced. In some older clans, I see them dropping farms before CvC is announced and then taking them back in.

KvK

The KvK page does not say how kingdoms are paired but I am assuming that the system is similar. I guess that kingdoms are placed in groups based on influence, then perhaps into groups based on number of phases won in previous KvK, then pairs closest in influence are selected. I am not sure but there may also be an element that excludes kingdoms that have fought each other before (or perhaps just recently).

Because the number of kingdoms is small, this will lead to some wild mismatches almost every week.

I would be interested in any thoughts on how either system could be improved.