https://github.com/AnInsomniacy/motrix-next/releases/tag/v3.9.0

Motrix Next has fully moved from the legacy aria2 engine to the maintained Aria2 Next engine

diff --git a/PKGBUILD b/PKGBUILD
index 04078e3..e82e7df 100755
--- a/PKGBUILD
+++ b/PKGBUILD
@@ -8,7 +8,6 @@ arch=('x86_64' 'aarch64')
 url="https://github.com/AnInsomniacy/motrix-next"
 license=('MIT')
 depends=(
-    aria2
     cairo
     gdk-pixbuf2
     gtk3
@@ -28,14 +27,6 @@ package() {
     # Extract the contents of data.tar.gz into the pkgdir itself
     tar -xf data.tar.gz -C "$pkgdir"

-    # Remove bundled aria2c — provided by the aria2 dependency
-    rm -f "$pkgdir/usr/bin/aria2c"
-
-    # Replace bundled aria2c sidecar with a symlink to the system package
-    local target_triple=$(gcc -dumpmachine | sed 's/-pc-/-/')
-    find "$pkgdir/usr/lib/MotrixNext/" -name "aria2c-*" -delete
-    ln -sf /usr/bin/aria2c "$pkgdir/usr/lib/MotrixNext/aria2c-${target_triple}"
-
     # Fix empty Categories so KDE launcher displays the app
     sed -i '/^Categories=/c\Categories=Network;FileTransfer;' \
         "$pkgdir/usr/share/applications/MotrixNext.desktop"

Using WEBKIT_DISABLE_DMABUF_RENDERER=1 motrix-next to sovle WebKitGTK issue. (If you are using with NVIDIA graphical card.)