+1 for forgejo and codeberg
Codeberg also has gadgetbridge, eternity for Lemmy, tenacity (new audacity without tracking), librewolf, kbin, fitotrack, fedilab, flomarkt (Facebook marketplace alternative), and a ton of other activity-pub specific projects on it.
Withing watches, sadly, are pretty shit for heart rate tracking though.
Garmin review, but this is his most recent graphs with heart rate correlation with ECG via the H10