After signing up, I decided I wanted to change my handle, which worked great. The only issue is that I seem to be stuck with my original handle as the reserved site subdomain for the <handle>.tngl.sh site. In the Settings->Sites page, I only have a single site for my old tngl.sh handle. Pressing the Release button does not change anything even after waiting for the 30-day cooldown referenced in the docs.
This is what my https://tangled.org/settings/sites page displays:
Maybe this is just a display issue? I have not attempted to use the site yet, but that's mainly because I wanted to get the domain name fixed before messing with it.
Thanks for the report! Looking into it.