enough memory for downscale ubuntu server?

Management decided to downscale prod server.

Current size:   Standard B16ms (16 vcpus, 64 GiB memory)
Desired size:   Standard B8ms  (8 vcpus, 32 GiB memory)

CPU is mostly idle (output is from sar -u)

10:20:01        CPU     %user     %nice   %system   %iowait    %steal     %idle
10:30:01        all     15.46      0.00      4.24      0.19      0.00     80.11
10:40:01        all     17.11      0.04      4.21      0.18      0.00     78.47
10:50:01        all     19.29      0.00      4.76      0.52      0.00     75.43

What I'm concerned by, it's the memory:

root@precious-server:~# free -h
              total        used        free      shared  buff/cache   available
Mem:            62G        7.9G         26G        510M         28G         53G
Swap:           0B          0B          0B

It seems I have 53GB available, however free value is only 26GB.

Sar reports 53%-57% is used(%memused field), out of which only ~15%-18% is being committed (%commit field):

10:20:01    kbmemfree   kbavail kbmemused  %memused kbbuffers  kbcached  kbcommit   %commit  kbactive   kbinact   kbdirty
10:30:01        28.9G     55.2G     33.9G     53.9%      2.6G     19.8G      9.7G     15.4%     24.1G      3.7G     11.5M
10:40:01        27.0G     53.3G     35.8G     57.0%      2.6G     19.8G     11.6G     18.5%     26.0G      3.7G      1.7M
10:50:01        26.8G     53.1G     36.0G     57.3%      2.6G     19.8G     11.8G     18.7%     26.2G      3.7G      4.3M

Grafana, reports only 15% of memory is being used:

So, you see my confusion? free command says I have 53GB available, sar says memory used is 52%, while Grafana says 15% used. I'm not sure I can do the downscale :)

What are your considerations gentlemen?