For personal use I created a simple bash script to batch convert large amounts of images from JPG to AVIF format.
Nothing fancy, but perhaps it helps someone else too.
Extract the compressed archive and move the folder to your C: drive.
Make sure the folder is named "jpg2avif".
Next add the "Convert JPG to AVIF" option in Windows right contextmenu
by double clicking the "Add to Contextmenu" file and confirming this action.
Remove the add the "Convert JPG to AVIF" option from the Windows right contextmenu
by double clicking the "Remove from Contextmenu" file and confirming this action.
Delete the folder "jpg2avif" from your C: drive.
Right click on a folder that contains JPG images and choose "Convert JPG to AVIF" to start batch converting.