The best place depends on the brand and type of fridge you are buying.
90%+ of compressor fridges (for RVs etc) are DC native. When they are listed as AC/DC this means that they have a power converter (like the one that powers your laptop) built in. This converts 120VAC to 12VDC.
If you have a shore power charger, there is no need for the AC option (it usually costs more). Your shore power charger will keep the batteries topped off and supply all the power the fridge needs.
I think a 60 liter fridge is a good size for a 7-10 days for 2 people. Any longer and you need more space. Of course this is highly individual dependent.
I have seen a few good reviews of the Whytner AC/DC portable fridges
https://bestoutdooritems.com/best-outdoor-refrigerator/ I cannot speak to power usage though.
Fridges with the Danfoss/Secop compressor system are quite reliable. Though they may not be as efficient as the Sawafuji compressors used in the Engel fridges.I like to watch YouTube videos of a similar theme when I'm looking for information about the right product. I hope this helps someone in the future. Good luck!