Many of the aliexpress/Amazon momentary switch kits come with those (but are coloured white)..
Eg https://www.amazon.com/Momentary-Tactile-Button-Switch-Assortment/dp/B07LCBLB8N/
So, for any other poor souls reading this post hoping for answers, I was able to order a multi-pack of generic tact switches (https://www.amazon.com/dp/B07LCBLB8N?psc=1&ref=ppx_yo2ov_dt_b_product_details) and I harvested the piece from the inside of the switch with the little red button and it fit well enough to work!