A truly lean team (say, <=5 people and limited project scope) should be able to live off their code forge's free CI/CD minutes, or whatever is included in the basic tier they're running. Just run the suite on a schedule against trunk instead of on every PR.
If not, then that's a good signal they should invest more into their CI/CD setup, and like you said it's not necessarily a huge investment, but it can be a barrier depending on skills.