dual-band access point

Hello,

Mikrotik dual-band SOHO access point really do not support “n” and “a” standards in 5 GHz?

This wrong, why do meen that?

Go back a few steps. How and why are you coming to this conclusion? What symptoms on which devices are you seeing?
Can you do an export of your wireless config so we can see a little more?

You can see it on Specifications page for all dual-band AP:

https://mikrotik.com/product/RB962UiGS-5HacT2HnT
https://mikrotik.com/product/cap_ac
https://mikrotik.com/product/hap_ac2
Image_mikr_ap.png
i do not see “a” and “n” for 5 GHz…

802.11ac is backwards compatible with both 802.11a and 802.11n standards.