I would think the files would be compatible, so long as you installed the correct software for reading those files.
Last I knew though, Windows 11 will only run on pretty modern CPUs. Windows 11 may not be compatible with your old hardware unless you also upgrade your CPU (which means also upgrading your motherboard and RAM).
PC World Magazine wrote:
At the moment, Intel processors compatible with Windows 11 date back to mid-2017 and no earlier. Think 8th-generation CPUs and beyond.
PC World Magazine wrote:https://www.pcworld.com/article/394793/what-cpus-can-run-windows-11.html
Currently, AMD processors approved for Windows 11 date back to 2018. For the most part, that covers 2nd gen Ryzen (Zen+) CPUs and beyond.
Some people have developed tricks for installing Windows 11 on older hardware. But if such a system is ever in need of serious tech support from Microsoft, they will probably refuse to help because it is not running on a "supported" platform.
You can probably get a reasonably affordable motherboard/CPU/RAM combination that would be a nice boost for your computer. This may be an opportunity for a more extensive upgrade.
If you aren't using the computer for gaming, you won't need more than a 12th generation Core i3. With modern Intel generations, Core i5 and higher is overkill in a non-gaming computer.
The AMD Ryzen 5 5600X would be a good top option for a non-gaming computer. It offers amazing performance for its reasonably low heat output.