katana15 bl2v laptop seems to not turn on whenever I bring it with me

For some context i am a college student who requires a laptop/pc for 90% of my course, So my laptop is an msi katana 15 b12v that is just over 2 years old, in the second year it started to take longer and longer too register that i had pressed the power button and boot up currently it can take an hour of attempts, although during the summer break it had started booting as soon as i press the power button until today when i went and brought it to college it started to not turn on for a long amount of time.

i had taken my laptop to a repair shop that stated to have cleaned and refitted everything checking for loose cables and such but the issue had continued not long after
its not a case of not being charged either
i had read that the PSU discharging can cause something like this but im unsure
i have left my laptop plugged in for several days to a few weeks plugged in and believe that may have caused the issue