Matching all elements in nested lists (irrespective of position) and returning matches with indexes

I have two lists x and y created from

x1 = list(c(1,2,3,4))
x2 = list(c(seq(1, 10, by = 2)))
x<- list(x1,x2)

x
[[1]]
[[1]][[1]]
[1] 1 2 3 4


[[2]]
[[2]][[1]]
[1] 1 3 5 7 9

and y,

y1 = list(c(5, 6, 7, 8))
y2 = list(c(9, 7, 5, 3, 1))
y <- list(y1, y2)

y
[[1]]
[[1]][[1]]
[1] 5 6 7 8


[[2]]
[[2]][[1]]
[1] 9 7 5 3 1

So basically, I want to get matches of x into y so I should just get '1 3 5 7 9' actually being a match. I am also needing indexes.

I have tried, I want to match the values irrespective of the position each x[[ ]] with each y[[ ]].

Matches <- x[x %in% y]
IDX <- which(x %in% y)

This does not work....

I would like something that can return matches of the same elements irrespective of positions per each list. This would be a rough idea of what I need...

  matches

        [1] False

        [1] 1 3 5 7 9

Thanks in advance, appreciate all the help.