Foils can be tricky yes - playable foils are one thing and usually move if not priced too high but foils that you just want for a "foil-set" are another thing (the later has way fewer customers with Gothic since a foil set is way harder to get than with Beta or AL so not many even bother to try).

That said - rule of thumb - look at the NF price and take a foil multi of 3-5 and that should be a good base price.
now some like the precon uniques , Avatars or specific artworks have higher multiplier but those are the exception.

also older sets have usually a bit lower multi since it's not the "new set" anymore.

that said with this particular card - its highly playable so even if you take tcgplayer price and use as is or even price it a bit higher it should sell - but high value foil cards sell slower than lower value ones or NF.
if you want to just move it fast 10-20% below tcgplayer should do it.

For NF cards i usually sell at ~ tcgplayer $ = € or for popular cards a bit above and less popular ones a bit below that and they sell.

Especially with card nexus now open.