You can replace this large certificate with one that only covers larksvik.no (probably the best course of actual to avoid confusion about where the certificates are stored on disk) via
sudo certbot certonly --cert-name www.larsvik.no -d www.larsvik.no -d larsvik.no --force-renewal
This should obtain a new certificate that covers only www.larsvik.no and larsvik.no, and effectively replace the current certificate with that one.
You can then run sudo certbot --apache 9 more times for each domain name that you want to cover with new, separate certificates. (You can specify the domains to cover with -d rather than interactively, if you prefer. Don’t forget to cover the forms both with and without a leading www.)
This might be nicer than deleting the old one (which can in principle be done with sudo certbot delete --cert-name www.larsvik.no), because if you deleted the old one you’d also have to change your Apache configuration that now refers to it.