If you go without the heatsink in the laptop due to clearance (WD lists the height somewhere on their page/datasheet), you an still get one separately. Icepc makes copper ones (also copper with graphene coating) at both 4mm and 2mm of height with the latter being useful in tight spaces.

edit

Checking WD's site, the original is 0.09" high while the heatsink version is 0.35". Datasheet has this as 2.38 and 8.80mm, respectively. The heatsink version does have some height on the back/rear, though. Icepc's 4mm and 2mm options would probably be shorter.

Is this the one?

https://www.amazon.com/icepc-DIY-Graphene-Heatsink-Performance-70x20x2mm/dp/B083FJTXNV/ref=sr\_1\_10?dchild=1&keywords=ice+heatsink+ssd+1.5+mm&qid=1631861043&sr=8-10

I'm going to order my S70 tonight

Actually ordered 2. https://www.amazon.com/gp/product/B07PS9S2DZ/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 and https://www.amazon.com/gp/product/B083FJTXNV/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1