Tested the same DisplayLink dock on an M5 Pro, M5 Air, and Neo. Only one actually benefits from it.
Got my hands on the Anker Prime DL7400 dock (DisplayLink-based, DL7400 chip, $299) and tested it across three Macs: my friend's M5 Pro, my M5 Air, and my girlfriend's Neo. Same dual 4K + 1080p vertical monitor setup for all three.
Results:
M5 Pro: Flawless but pointless. It natively supports up to 4 displays via its three TB5 ports and HDMI 2.1. The dock adds a software rendering layer on top of hardware that doesn't need it. You're paying $299 for one cable instead of ten. Fine if you care about desk aesthetics, but functionally unnecessary.
Neo: Works but barely. Three displays lit up, which is technically impressive for a $599 laptop with a binned A18 Pro chip. But the DisplayLink software rendering layer is heavy for this silicon. Mouse drag is noticeable, multi-screen video stutters, and Chrome with a lot of tabs across three monitors gets laggy. Used the same dock on the M5 Pro and the difference was night and day --- the bottleneck is the chip, not the dock. Fun experiment. Not a daily driver.
M5 Air: The actual sweet spot. This surprised me. Three displays, smooth performance, indistinguishable from the Pro experience for office work (Figma, browser, Slack). The Air natively caps at two external displays --- DisplayLink bypasses that limit and the M5 chip has enough headroom that you don't feel the overhead. Plus you finally get an SD slot and ethernet, which the Air still doesn't have built in.
The display limit caveat: DisplayLink is 60Hz max. If you're coming from a 120Hz ProMotion display, you'll notice. This is fine for office work, but definitely not for gaming or content creation that needs high refresh rates or high bandwidth.
TL;DR: On the Pro, the dock is a luxury (already natively supports 4 displays). On the Neo, it's a weekend experiment (chip bottleneck). On the Air, it genuinely unlocks something the hardware can't do natively --- third display, full port expansion, $299. That's where the value actually is.