This is a bug known and already fixed upstream (https://github.com/qgis/QGIS/issues/61951). Error messages include: sip-build: class 'QgsTopologicalMesh::Changes' has not been defined Reproducible: Always
Created attachment 930381 [details, diff] Patch fixing compilation with sip>=6.11 Patch from https://gitlab.archlinux.org/archlinux/packaging/packages/qgis/-/blob/497b127c70a0ab600cd5083e5aba432b3088abd2/qgis-sip-6.11.patch Arch issue: https://gitlab.archlinux.org/archlinux/packaging/packages/qgis/-/issues/4