I maintain some project on all forges in parallel, even savannah. Savannah is even the default. But 99% of all reports and contributions are on the github mirror, 1% on savannah, 0% on gitlab and 0% on codeberg. Nobody cares about those islands.

issues are stored in git bug and automatically synced. Github is the only viable option, but you can keep the others as mirrors when github chooses to strike you.