I'm a huge fan of Gitea but saying that GH Actions are supported is a bit of a stretch. Everybody asked for CI/CD so they started working on it and yes you can test it but nobody sane would use it in a production setting.
Try running act against their own act fork and watch it vomit. I first had contact with act trying to get VSCodium to build locally, since their build system is/was entirely GitHub Actions based. The "well, that didn't work" was horrific to troubleshoot
git clone https://gitea.com/gitea/act.git
cd act
make build
./dist/local/act -j lint -W .github/workflows/checks.yml --verbose workflow_dispatch
echo good luck
