Here's a direct URL for coverart if anyone needs it.
Dee&zer v1.0#Cover Art (&Direct by WWW).src
# Mp3tag Tag Source for Deezer v1.0 #
# #
# Created by vikaesar #
# Modified by stevehero 2021.02.13 #
# #
# KNOWN ISSUES: Genre information can't be parsed as it is not provided #
# by Deezer. #
# #
# When parsing multi-disc albums with more than 20 discs #
# then the total tracks for every disc past the twentieth #
# one aren't parsed, so their %track% field won't follow #
# this pattern: "track number/total tracks", it will just #
# show the track number. #
# #
# INSTRUCTIONS: This file needs to be stored in Mp3tag's tag sources #
# directory: #
# %APPDATA%\Mp3tag\data\sources #
# #
# CHANGELOG #
# #
# [2019-05-25] v1.00 Initial release #
# [2020-04-08] v1.01 Artwork only 1200px #
################################################################################
[Name]=Deezer
[AlbumUrl]=
[BasedOn]=www.deezer.com
################################################################################
# ADJUST TAG INFORMATION DIALOG #
################################################################################
[ParserScriptAlbum]=...
## Comment/uncomment for debugging purposes:
# DebugWriteInput "C:\Users\your_username\Desktop\mp3tag-deezer-ws-album-debug.out.html"
# Debug "ON" "C:\Users\your_username\Desktop\mp3tag-deezer-ws-album-debug.txt"
FindLine "<script>window.__DZR_APP_STATE__"
RegexpReplace ".+<script>.+ = " ""
RegexpReplace "</script>.*" ""
json "ON" "current"
## First, parse album data
json_select_object "DATA"
# Cover
OutputTo "COVERURL"
json_select "ALB_PICTURE"
Say "https://e-cdns-images.dzcdn.net/images/cover/"
SayRest
## You can choose the cover resolution here, up to 1200px x 1200px
Say "/1200x1200.jpg"
# Say "/512x512.jpg"