Doing some test with scaleway at the moment, looks pretty solid.
the 3€/month starter vps (vc1s) cloud does the job, it won't transcode though. I'm going with this one for the moment as I like to optimize my file before sending it to ACD using rclone so all my movies are playing fine even if plex can't transcode it (x264 and aac, mp4 or mkv doesn't matter it will direct stream anyway) and that's exactly what I was looking for (never found the option to forbid transcode on plex...) and the 200m Unmetered bandwidth is sweet for multi user.
The 12€/month bare metal vps (dedicated cpu C2S) is able to transcode up to 3 devices of mine at the same time (low rez though, haven't tried with 3x1080p) 300m Unmetered bandwidth with it, good stuff.
Once I'll be done uploading my 6TB of holiday movies to ACD I'll try with their arm server. Not sure it'll be able to transcode at all...