This question was posted regularly on Reddit (no one every thinks to search for the answer first..) so I thought I'd create a pinned post with my own thoughts on it - but of course I'd love to hear other suggestions in the comments!
Autechre have a huge discography, so many hours of music, it can understandably be a bit daunting to know where to dip in.
My own personal feeling is that if you jump in with something very recent, depending on your tastes, you might find it difficult to understand or appreciate - and I've always felt that their new releases are informed by the entire evolution of their works over the past 30+ years.
So in my mind, if you've never heard any Autechre, start at the beginning, listen to each album and get to know it before you move on to the next one.
Here's a list of all their albums
https://www.discogs.com/artist/41-Autechre?type=Releases&subtype=Albums&filter_anv=0
But of course don't forget the EPs too - which have often come out after an album and can feel related to that release. For example, when Oversteps came out I found it confused me - it was far removed from what I expected - but when they released the Move of Ten EP, then it made a lot more sense to me.
And sometimes, an album comes out and on first listen you might be "WTF is this?", and to be honest, I've often found the albums that seemed least accessible on first listen have been the ones that grew on me the most over the years.
Anyway - please add your own thoughts below, and hopefully people new to Autechre will find this discussion useful!