I can recommend Andy10gbit#8093 discord server at https://discord.gg/RHhHbK8vx2 . He resells dedicated cloud servers from Hetzer, Leaseweb, NForce and OVH and his OVH lineup in particular has a few GPUs in his lineup. He lists them for Plex transcoding but I think you can ask him to not install any software on the box and lease it to you directly.

His response time is not the best as he's really busy with clients, it took him a few days to get back to me, but he's flexible and offers refunds if things don't work out, like he did for me.

He doesn't have a website though, all support/sales is done P2P through Discord.