Ok, It Is a good thing that we are back to normality.
So the issue Is somehow on the Ubuntu server.
Since It works with another PC, power supply Is NOT and issue, but It Is completely "wrong" (generally speaking).
JFYI:
Some Mikrotik devices (including yours) can be powered at 5V through an USB C connector.
The use of an USB C connector does not imply USB C Power delivery compatibility.
If you use an AC to 5V Power supply with an USB A socket and and USB A to USB C cable, the connection will be limited by what the power supply can delivery (a 1A@5V will be able to give 1A, a - say to exaggerate - 12A@5V will be able to give 12A.
Adapters with an USB C socket may - if they do not respect the standard - behave the same, but if they are actually compliant to standard they won't deliver more than 0.9 or 1.5A.
As well, if you try powering a device from a USB C Port (say from a laptop) or from a plain USB A (3/3.1) of a desktop you won't get more than 0.9A, 1.5A if USB 3.2, because the max current out of an USB 3/3.1 port Is 900 mA or 1500 mA for 3.2 (was 500 mA for USB 2) according to standard.
USB C can deliver not only 5V, but also 9V and higher voltages, so It needs to negotiate with the powered devices.
This negotiation Is complex BUT a simplified version exists that can allow delivery of up to 3A@5V.
Mikrotik devices miss however this provision (two 5.1 KOhm resistors towards ground) so without a mod/hack they cannot be fully powered from a fully compliant USB C source.
Details here:
Very likely your device Is 7W or less, so It draws less than 1.5A@5V and everything Is working, but if you try the same with a more power hungry device results may vary.