Are there any good RAID(-like) platforms where drive size doesn't matter and you can just throw random drives at it?

@north something like Linux's Logical volume Manager?

https://opensource.com/business/16/9/linux-users-guide-lvm

A Linux user's guide to Logical Volume Management

Managing disk space has always been a significant task for sysadmins. In this guide, learn how LVM can make managing storage easier.

Opensource.com
@BigMalCampbell There isn't any sort of redundancy, is there?

@north
I haven't done this myself but raid is supported

You can create and manage Redundant Array of Independent Disks (RAID) volumes by using logical volume manager (LVM). LVM supports RAID levels 0, 1, 4, 5, 6, and 10. An LVM RAID volume has the following characteristics:

https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/8/html/configuring_and_managing_logical_volumes/configuring-raid-logical-volumes_configuring-and-managing-logical-volumes

Chapter 9. Configuring RAID logical volumes | Configuring and managing logical volumes | Red Hat Enterprise Linux | 8 | Red Hat Documentation

Chapter 9. Configuring RAID logical volumes | Configuring and managing logical volumes | Red Hat Enterprise Linux | 8 | Red Hat Documentation