What RAM for Intel® Core Ultra Series 1

I am about to pre-order the FW 13 Ultra 7 155H. I have my own storage and would like to probably purchase my own RAM as well. I will almost certainly be using Linux. Is there a list of compatible memory? I have found some posted for previous models, but nothing for this one. I will almost certainly get 64GB, so I’m assuming that means 2x32GB. I am in Canada, if that matters (much is not available here).