Thanks for the question!
As mentioned by CrazyKats, do run the HealthCheck app first to see if your computer would be supported to run Windows 11 builds. That's step one.
For your other question about "breaking" a PC, allow me to clarify further what I believe you may mean and reply that way. Hopefully it'll provide the insight(s) that you're looking for.
Preview builds of Windows can't "break" a computer so-to speak, at least not in the sense that if you install one your mouse is going to explode or your CD-ROM drive will experience a physical failure all the sudden. :)
I think you're asking about bugs, and yes, there are bugs in preview builds. We work hard to keep the OS code as clean as possible, but bugs are a part of the software world and they can cause unwanted side effects at times.
Is it possible that you'll have a driver conflict and your graphics may not appear like you'd expect? Yes, that's possible. Could there be a bug that may prevent you from using a specific application that you like? That has happened as well. The list goes on, but as you noted, part of the fun of running preview builds is finding the bugs and sharing your experience! That's why we have the Feedback Hub app.
One thing related to "breaking" that you may consider is hard drive usage. Especially on older hard drives that have seen a lot of read/write usage over time, the very nature of how hard drives work puts them in a state where they will physically fail at some point. Just the nature of mechanical devices. Is it possible that could happen while running a preview build of the Windows OS? Sure. Is the Windows OS itself going to cause that? No reason to believe such a thing has or would potentially occur. Drives wear out from cycles, not because of what is written to them.
To sum it all up in a shorter way: it is possible that bugs may cause unwanted/unexpected behavior of your computer, but I am not aware of anyone having a permanent "break" of physical hardware because of an OS build.
I realized I missed answering your final question: "So I was wondering if it does break will Microsoft replace it or if it's on me?"
Unless there is a problem with Microsoft hardware that is under warranty (which is separate from the Windows Insider program altogether), Microsoft does not provide file recovery, software replacement, or hardware replacement for program participants.
If you join up, please do be sure to read the program agreement / terms of use; lots of good information in there!