How to read multiple files from multiple directories with here

Question

I have an R project located in a root folder and I would like to open all excel files that are in the subfolders of the project. All these subfolders have an identifiable pattern. From the existing threads, this is what I tried so far:

library(here)
library(readxl)

dirs <- list.dirs()
dirs <- dirs[grepl("^./SDG.*", dirs)]
df.list <- lapply(dirs, read_excel)

The 'dirs' object contains all the subfolders I need to look through, but I get an error after the lapply function:

Error in file(con, "rb") : cannot open the connection
In addition: Warning message:
In file(con, "rb") : cannot open file './SDG 1': Permission denied

I also tried to look through one folder at a time but I also get an error:

file.list <- list.files(here("SDG 1"), pattern='*.xlsx')
df.list <- lapply(file.list, read_excel)

Error: `path` does not exist: ‘Filename.xlsx’

I cannot simply open all excel files across all folders as I do not want to have the Excel files from the root folder of the project. Thanks in advance