If you want to turn off DoH right now, see https://codeberg.org/librewolf/issues/issues/2029#issuecomment-2281388

More info: https://codeberg.org/librewolf/issues/issues/1975#issuecomment-2281407

Seems like it's similar to https://reddit.adminforge.de/r/LibreWolf/comments/1f4ush4/

Does the same happen for you on the official portable version? https://gitlab.com/api/v4/projects/44042130/packages/generic/librewolf/128.0.3-1/librewolf-128.0.3-1-windows-x86_64-portable.zip

If not, try contacting the maintainer on the Portableapps.com forum.