How to organize a workflow with periodic copying of one git branch to another?

Question

git

Such a workflow:
1) there is a release-branch (few commits) and dev(many commits);
2) from time to time, a volitional decision is made that it devis good enough and its contents are copied into release, after which both branches become identical , regardless of any conditions;
3) after that, work continues in both branches: where more, where less.

Question: how to organize this? (In terms of git commands.)

It would be possible to periodically merge devin release, but I don’t want to get surprises like "nothing to merge" (false in this context), so, I suppose, the banal merge is no longer needed.

PS I hope the workflow isn't too offensive; I propose to take it for granted.