Recommendations for EF to RF Adapters with Drop in Filters

[ilanafiner]

Hi! I'm looking at the various EF to RF adapters with drop in filters. I see there is one for ND and one for polarizing. If I buy one can I buy just the drop in of the other? Like if I buy the ND one can I buy just the drop in polarizing filter or do I have to buy them separately? (Yes I know I can buy one for the front of the lens but that's not the question/answer I'm looking for)

[SignifDigits]

I don't have one and have no first-hand experience, but a quick search of the internet shows various Canon and third-party filter options  - clear, ND, and polarizing can be inserted into the adapter.  I found a picture at the lensrentals site that showed the ND version disassembled with the option to rent a clear insert.  I was unable to find all of the parts on the Canon web site but it appears you can contact a Canon reseller and purchase only only one adapter and then purchase and drop in the other filters separately.