Although it's too soon to say if Denuvo will negatively impact Battle Network Legacy Collection, the third-party tech is notorious for hindering gameplay performance, among other annoyances. Seeing as the collection is made up of Game Boy Advance ports, it shouldn't be too severe. But for the brand-new PvP modes? Uhhh... we'll have to see.
The good news is Capcom typically remove Denuvo from their games a good 6-12 months after release. In some cases, like Mega Man 11, the tech is patched-out sooner due to a crack. Either way, keep those fingers crossed for a smooth launch.
Mega Man Battle Network Legacy Collection is due on Nintendo Switch, PlayStation 4 and PC/Steam in 2023.
Source: The Rockman EXE Zone