Well this is quite the puzzling situation indeed. I've tried some options on my end but it still appears that this particular game just constantly freezes. It could very well be the ROM but I've tried 3 already, puzzling.
Thanks for your assistance! I'm going to keep seeing if I can get this to work!
Okay an hour later and I found some INTERESTING stuff!
The intro is fine, battle Numemon and go to Digibase all is normal. (Roughly 20 minutes in, the intro is long as heck.)
Proceeding down to the eventual fight with UNO, DOS and TRES is where the random freezing start and I do mean random.
=Known freezing events.=
-The cutscene with UNO, DOS and TRES before their boss fight freezes every time.
-Digimon attacking can sometimes lead to a freeze.
-Leaving an encounter can cause a freeze.
-While rare, opening the menu can cause a freeze.
------------------------------------------------------
I've tried multiple methods in order to fix these issues.
Twilight Menu: v19.0.0|NDS-Bootstrap: v0.37.0|NDS-Nightly: v.0619341a
I AP patched the ROM myself which didn't have an effect from what I gathered but more testing is needed.
I used multiple ROMs from different sources.
Tried Robz8's suggestion of running it through Nightly which did help as the boss cutscene froze later then it did before.
I even went through cheat menus and going through AP patching like that.
------------------------------------------------------
Why am I so dedicated to this? I'm a Digimon fan and I think more people should be able to play Lost Evolution! My testing may be able to assist others so that's why! Especially prior to the eventual English translation release!
I dunno if these detailed thing will help just thought I'd share what I found while messing with it!