So you can’t use the front page of feddit.online through beehaw, you will need an feddit.online account for that. However, the same posts on feddit.online (most I see on the front page are from beehaw, Lemmy communities or kbin.social), you can participate from beehaw. For example https://feddit.online/m/[email protected] is roughly equivalent to https://beehaw.org/c/[email protected]