I have several different Samsung ear buds, including the Buds 2 Pro. I cannot get these to seal at all and nothing I do can possibly make the Wearable app test "good fit". They stay in my ears better than all of my others as they seem to fit the cartilage perfectly but they are not long enough to go into my ear canal so no matter what tips I use they do not seal. The Buds 2 seal MUCH better but they do seem to creep out of my ears until eventually fall right out. I just bought a set of Azla Sedna tips that seem to have fixed that problem (though I have only worn them for a few hours and one gym session so far) so I'll probably send my Buds 2 Pro's back. The noise cancellation difference between Buds 2 and Buds 2 Pro is HUGE win for the Buds 2, as long as with the right tips they stay seated.
I recommend trying out the Buds 2 with the Azla tips and if you don't immediately like them, take them back. You can buy them outright on the Samsung website or finance them for like $4 a month. If you decide to trade in your Buds 2 Pro's you can order them, try them out, and if you don't like them just keep your Buds 2 Pro (You have a couple weeks to send them in case you change your mind) and should be able to return the Buds 2.
Another option: I have a set of Soundcore Liberty Neo that will not budge in your ears. They are the only set I've ever used that no amount of running, sweating, and even swimming (they work under water) will move them. They are MUCH cheaper than the Samsung so don't sound quite as good and don't have all the fancy features but will drown out all outside noise and never move. They come with a bunch of different size tips and a bunch of different size hook things that make them lock into your outer ear cartilage (painlessly) which should solve your issues with different size or shape ears. This is the Amazon link from when I ordered them though not sure why the case is now black instead of the red I got (probably updated model). For sub $50 they are well worth trying out.
https://www.amazon.com/gp/product/B07WCNV4MP/ref=ppx\_yo\_dt\_b\_asin\_title\_o09\_s00?ie=UTF8&psc=1