Thinkpads – a laptop with a rich history of Linux use – can be bought with an integrated 4090. The ThinkPad P1 Gen 6 can be configured with an i9, plenty of flexibility for drive space and RAM, and an RTX 4090. It’ll run you, even used, around $3k to $4k, which is the equivalent of a desktop replacement. But it’ll be pretty doggone compatible with any Linux distro you’d like.