I have purchased v-bucks on the PC but they are not showing on my Switch.
Both the answer to this question and the FAQs it quotes suggest I should not expect it to work the other way around (that is, v-bucks bought on the Switch won’t appear on the PC) but they both imply it should work the way around I’m doing it:
If you buy V-Bucks on PC or mobile, they are shared if you have your Epic account linked.
V-Bucks purchased on Nintendo Switch, Xbox One, and PlayStation 4 are only available on the platform they are purchased on. All other V-Bucks, are available across platform.
Although the example the FAQ page uses does seem to contradict this:
Example 1:1000 V-Bucks purchased on PC.
◦ PC will display 1000 V-Bucks available.
◦ PS4 will display 0 V-Bucks available.
Which is correct, or have the rules changed since these were written?