I wouldn't take this at face value. Modern OSes are great at managing RAM, which means RAM only gets cleared as needed. A lot of that 27 GB can likely be cleared, but the OS finds that there isn't any reason to.

I somehow doubt that. Look at Cached files and subtract that number from Memory used, and tell us please that number.

No "free" command. With "top" command I got this:

MemRegions: 1744370 total, 5771M resident, 234M private, 4726M shared. PhysMem: 31G used (2888M wired, 15G compressor), 74M unused.

A bit confusing even for someone who is comfortable dealing with low level kernel stuff...

I guess I'll need to install Homebrew, MacPorts or something.

Edit vm_stat says this. Looks like more reasonable output:

  % vm_stat
  Mach Virtual Memory Statistics: (page size of 16384 bytes)
  Pages free:                                4070.
  Pages active:                            387530.
  Pages inactive:                          385599.
  Pages speculative:                          241.
  Pages throttled:                              0.
  Pages wired down:                        185222.
  Pages purgeable:                              2.
  "Translation faults":                 458286513.
  Pages copy-on-write:                   18032218.
  Pages zero filled:                    230111374.
  Pages reactivated:                      9982494.
  Pages purged:                           4086524.
  File-backed pages:                       197104.
  Anonymous pages:                         576266.
  Pages stored in compressor:             2007280.
  Pages occupied by compressor:           1062310.
  Decompressions:                         6355861.
  Compressions:                          10204603.
  Pageins:                               13150790.
  Pageouts:                                252630.
  Swapins:                                     52.
  Swapouts:                                 30380.

Better to use Activity Monitor, as simple as that might be.

FWIW, with only Chrome (several windows, multiple tabs, rebooted a few weeks ago) open I'm at:

Physical Memory: 32,00 GB

Memory Used: 21 GB

Cached Files: 10,45 GB

Swap Used: 0 GB

You can look at any number of videos demonstrating that a base model MacBook Air is more than capable of running Chrome with a few tabs open. Modern browsers (and operating systems) opportunistically use free RAM for caching.

SW dev stuff tends to take a lot more RAM than consumer/productivity apps though. I would want at least 16 and ideally 32 for software dev. But for general usage I think that would drop to at least 8 ideally 16.