Diablo II: Resurrected has been out in the wild for over a month, no doubt bringing delicious nostalgia for fans despite server issues that rumbled on for far longer than desired. It's an interesting release from a technical perspective, as it remasters a game from 2000 with updated visuals and performance, while also arriving on a broad range of systems - including the Switch, of course.
Digital Foundry has produced a video breaking down performance, though it always feels a little unfair when Switch is put up against PS5 and Xbox Series consoles - the counter-argument would be that those are the 'current-gen' systems, which is a decent point. In any case it's an interesting analysis, especially in light of Diablo III: Eternal Collection being pretty solid on Nintendo's system back in 2018.
The video at the top of the page is worth a watch, but the summary seems to be that the Switch version is a competent effort. It's 30fps performance seems quite stable, while resolution is typically 900p docked and 720p portable (though it scales down as low as 480p in portable mode at some points, apparently).
It is worth noting that some of the comments on the video suggest that the game can buckle on various platforms in higher difficulty settings or in later, busier parts of the game. The DF assessment is very much based on early parts of the game.
In any case it's always interesting to see Digital Foundry's technical breakdowns of Switch releases; this seems like a pretty reasonable port for the hybrid system.