Things to check/try:
Latest homebrew launcher
https://3ds.guide/finalizing-setup
Latest Luma boot.firm
latest version of the 3dsx app.
as for downgrading luma... you can try downloading the 7.1 boot.firm from
https://github.com/AuroraWright/Luma3DS/releases and see if it works.
But you may have to downgrade boot9strap too... Maybe flash a nand backup with out protecting the firm would maybe downgrade that... I don't know.
HONESTLY I would just wait a several weeks for things to get fixed up on the current stuff and then go from there.