How to rename mutliples columns names (with prefix) according to respective dataframe name [R]

I have 15 dataframes, that I have merged together.

1. Here I'm loading my files.

data_files <- list.files()  # Identify file names
                       

for(i in 1:length(data_files)) {                              
  assign(paste0(substr(data_files[i],1,nchar(data_files[i])-4)),             
           read_excel(paste0("",
                           data_files[i])))
}

Problem, they have the same columns names. That's why i want to rename the columns with the following code :

colnames(COMMUNITY)
 [1] "OBJECTID"                   "SOURCE_ID"                  "mean"                       "LMiIndex Fixed 450000 RS"  
 [5] "LMiZScore Fixed 450000 RS"  "LMiPValue Fixed 450000 RS"  "COType Fixed 450000 RS"     "NNeighbors Fixed 450000 RS"
 [9] "ZTransform Fixed 450000 RS" "SpatialLag Fixed 450000 RS"

colnames(COMMUNITY) <-paste("PREFIX",colnames(COMMUNITY),sep="-")
  

I would like to do this to my 15 dataframes, so I tried this :

List_df_EU = list(COMMUNITY,CSR_STRATEGY, EMISSIONS,ENV_PILLAR,ESGCOMBINED,ESGCONTROVERSIES,
                  ESGSCORE,GOV_PILLAR,HUMANRIGHTS,INNOVATION,MANAGEMENT,PRODUCT_RESP, RESSOURCE_USE, SOC_PILLAR, WORKFORCE)


for(i in 1:length(List_df_EU)) {                              
  colnames(List_df_EU[i]) <-paste("AS",colnames(List_df_EU[i]),sep="_")
  
}

It doesn't work, and, I don't know how to retrieve dataframe name, in order to put him as PREFIX of columns.
I could do it for each dataframe seperately, but it would take a long time, and would not be very clever. Even after many web researches, I never found something that was automated.

After that, I use the following line of code to merge, It actually works, but as expected every colnames are identical.

Merged_file <- purrr::reduce(List_df_EU, dplyr::left_join, by = 'OBJECTID', suffix = c(".x", ".y"))

First, refer to elements of the list with double square brackets, like so List_df_EU[[i]] (List_df_EU[i] is a sub-list of 1 element, not the element itself).

Second, we could create List_df_EU with tibble::lst() instead of list(), so that elements are automatically named. Then, "AS" can be replaced with names(List_df_EU)[i].

List_df_EU <- tibble::lst(....)

for(i in 1:length(List_df_EU)) {                              
  colnames(List_df_EU[[i]]) <- paste(
    names(List_df_EU)[i], colnames(List_df_EU[[i]]), sep = "_")
}

Edit
To allow the subsequent join on OBJECTID, we could rename all columns but OBJECTID, for instance using dplyr that has a nice interface for this:

for(i in 1:length(List_df_EU)) {                              
  List_df_EU[[i]] <- dplyr::rename_with(
    List_df_EU[[i]],
    ~ paste(names(List_df_EU)[i], .x, sep = "_"),
    .cols = - OBJECTID
  )
}