Flatpak slow start

Could it be an appstream or systemd issue? There are updated 11.11 and 10.11 respectively, probably 16-17 I face the issue, I have internet issue 13-15, no good internet connection on these days.
I'm using build repo, no use of kde-next at all.

Is that similar https://bugzilla.redhat.com/show_bug.cgi?id=2247905? But the issue is not only to Firefox but gtk applications, I'm using gtk applications in flatpak.

For some unknown to me reason I cannot build appstream 0.16.3 (0.16.4 is in the main, I deleted automatically older versions from cache)
PKGBUILD

pkgname=appstream
_pkgname=AppStream
pkgver=0.16.3
pkgrel=1
pkgdesc="Provides a standard for creating app stores across distributions"
arch=('x86_64')
url="https://github.com/ximion/appstream"
license=('GPL')
depends=('libyaml' 'libxml2' 'glib2' 'qt5-base' 'libxmlb' 'libsoup')
makedepends=('meson' 'ninja' 'gobject-introspection' 'itstool' 'xmlto' 'gtk-doc' 'gperf' 'qt5-tools') # 'clang')
source=("https://www.freedesktop.org/software/appstream/releases/${_pkgname}-${pkgver}.tar.xz"
        'appstream.hook'
        "https://github.com/ximion/appstream/commit/306eb287a36a2779c304fe47b5473e468c7bd0f6.diff")
md5sums=('d60cdc2c2641398c2fde38e6436d185b'
         'SKIP'
         'cff1cb4cab86ecdc534abc3c63a1fd90')

prepare() {
  cd ${_pkgname}-${pkgver}

  #patch -p1 -i ${srcdir}/306eb287a36a2779c304fe47b5473e468c7bd0f6.diff
}

build() {
  mkdir -p build
  cd build

  #export CC=/usr/bin/clang
  #export CXX=/usr/bin/clang++

  meson setup ../${_pkgname}-${pkgver} \
    --prefix=/usr \
    --buildtype=release \
    --libdir=lib \
    --libexecdir=lib \
    -Dqt=true \
    -Dstemming=false \
    -Ddocs=false \
    -Dmaintainer=false
  ninja
}

package() {
  cd build

  DESTDIR=${pkgdir} ninja install

  install -Dm644 ../appstream.hook ${pkgdir}/usr/share/libalpm/hooks/appstream.hook
}

FAILED: docs/appstreamcli.1 
/usr/bin/xsltproc --nonet --stringparam man.output.quietly 1 --stringparam funcsynopsis.style ansi --stringparam man.th.extra1.suppress 1 -o docs/appstreamcli.1 http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl ../AppStream-0.16.3/docs/xml/man/appstreamcli.1.xml
I/O error : Attempt to load network entity http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl
warning: failed to load external entity "http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl"
cannot parse http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl
[45/206] Generating 'qt/libAppStreamQt.so.0.16.3.p/moc_appstreamqt_export.cpp'
../AppStream-0.16.3/qt/appstreamqt_export.h:0: Note: No relevant classes found. No output generated.
[57/206] Generating GObject enum file src/as-enum...use command contains newlines, to capture output)
ninja: build stopped: subcommand failed.

It doesn't fix the issue. Probably another change of sub depend? Did you know who provide access to DBus to flatpak? Or qt5-base change?

I don't have previous version, I could test if you provide it.

It looks like xdg-dbus-proxy is split from flatpak repo, could it make difference?
https://gitlab.archlinux.org/archlinux/packaging/packages/flatpak/-/blob/main/PKGBUILD?ref_type=heads#L101
Failed to create DBus proxy for org.freedesktop.UPower