I'm not sure if it's because I have been searching face mills on aliexpress for the past few days but when I tried to google anything to do with BAP300R all that came up was places selling face mills probably 90% of the links were aliexpress. After going 3 pages deep on google I would try something a little different and get the same results.
Welcome to the confusing world of Ali Express. You might be trying to find something that doesn't exist. Not everything sold there complies with standards. And even if it does use industry standard terms, they may not be right. The outfits that sell on Ali are mostly all little mom & pop shops in China that acquire stuff by Lord knows what method from a factory and then sell on Ali.
As far as I can tell, they are just different size range ratings of the same thing. Sort of like BXA and AXA tools. Here is a chart I found on Amazon:
Note that both sizes cover 2" but you can't get the smaller one in the bigger size from that seller and you can't get the bigger one in the smaller size. Since insert standardization is a worthy goal for hobbiests, I'd pick which ever one has inserts you are more likely to use elsewhere.
In my case, that's the bigger one of these two with the APKT1604 inserts. However, I was able to find other smaller diameter tools that use this same insert. In fact, I have a drill that uses these inserts.
Different inserts is an ugly monster to a hobbiest guy like me. Once you have the size, you also need them for different materials (inserts for steel, aluminium, SS, Cast iron, etc) and also several different nose radii for each. The last thing I want is a different size insert with all those variations. So, when I buy tools, I always buy ones that use the size and style of insert that I standardized on.
I don't know where you are on your insert learning journey. I'm relatively new with just a year of actually using them under my belt. But before that I prolly spent 3 years learning about them to avoid mistakes.
Keep in mind that a set of fly cutters with HSS bits will do everything a face mill will do. Just slower and needing less hp.