You can disable GPG key on the added repo, by inserting 0 instead of 1 as shown below,
vi /etc/yum.repos.d/mongodb-org-7.0.repo
[mongodb-org-8.0]
name=MongoDB Repository
baseurl=MongoDB Repositories
gpgcheck=0
enabled=1
gpgkey=https://pgp.mongodb.com/server-8.0.asc
or you can import gpg following,
sudo rpm --import https://www.mongodb.org/static/pgp/server-8.0.asc