How to force Linux cache not to replace ZFS cache?

Question

linux

Good afternoon. I will install a system with ZFS as the main fs, but with frequent connection of external drives, etc. Accordingly, when using them, the Linux cache will grow and force the ZFS cache to decrease. But this is not necessary, since caching is not important on the rest of the fs. It is necessary to force the Linux cache to remain at a minimum. What are the options?