@Thaddy.
Thanks a lot. I think this is the best approach. Not by avoiding pipes (free -h, lscpu, etc.), but because these files are not really files but descriptors mapped to memory. Now I'm going to compare the speed to parse with (grep-awk) vs FPC Internal (pos-posEx).
@Markmll.
Thank you for your comment. Developing in wide-spectrum for *nix is not easy, but not even within GNU/Linux variants. Nor do I think the matter improves. Systemd debate, variants with non-Linux kernels, sandbox applications of different moralities (FlatPak, Snap, Appimage). Nowadays, the simple fact of showing a system notification is no longer standardized.
As if that were not enough, assuming that "ps" will run magically on all systems, it seems that the data that draw are inaccurate (in multi-thread, much more).
Fortunately, my target for this topic is only pure Debian 9-11, with which I think reading from /proc will be the most appropriate at the moment.
I think this will be enough for me:
RAM: /proc/meminfo
CPU: /proc/cpuinfo
SELF: /proc/{myPID}/smaps