Linux friendly from what perspective? You want a NAS that can work with Linux? If all you are talking about is file sharing, then they pretty much all are. Linux can connect to SMB or NFS shares without hassle.
If you want to use things like their proprietary backup apps then there are more things to consider.
On the other hand, if you want to replace the installed OS with Linux, there are some appliances that allow that. Terramaster and Ugreen for example. However, I don’t recommend that. You are paying a big premium for these devices over just buying a chassis without an OS if you want to install your own.
I recently switched from a Synology to my own appliance running TrueNAS Scale. You can find that story here.
In either case, my recommendation would be to start with understanding your needs and objectives:
- How much storage do you need?
- Do you need/want SSDs and is your network fast enough to support that?(Generally, you can saturate a 1GB network with HHDs.)
- Are you only trying to share files or do you want something more. Some NAS solutions also offer other things:
- Proprietary or open source backup solutions
- Kubernetes or docker containers
- The ability to run virtual machines
- VPN integration
- Snapshots
- Etc, etc
Answering these questions will help guide you to the right solution. For example, if you literally only want to share files over SMB or NFS, that requires very little. On the other hand, if you want transcode 4K video or host many virtual machines, that would lead you to a different solution.