a little niche cuz they're primarily a game server provider but nuclearfallout is the most proactive provider i've seen to do this, on vps or dedicated hardware. there has been many times they've worked with upstream bw providers and automatically holed incoming ddos, noticed packet loss and abnormal routing etc, before even reaching end user interfaces-

been using them for decades and they've been incredible for this, at least for the US options (prem/internap)