Who said that If unplug the ECU fuse would 100% disconnect the power supply to ECU ?
Some Vehicle , Have a Few positive wire connect to ECU. and it does not ONLY go through ecu fuse.
and also , there's a Backup power supply connect to ECU to keep the settings / memory / error code in ECU
and also , this Power supply does not go through ECU fuse .
it goes through other fuse like MAIN Fuse etc.
So , in return , Disconnect ECU WOULD Not reset the ecu. ONLY Unplug ECU socket , or DISCONNECT battery would helps .

But , Be aware of immobiliser car. Battery disconnection would reset and change the immo code. and den u hav to go back toyota to Make new set immo + key. Price ? maybe 1k .

my suggestion : go to the workshop who hav MAchine to check ur engine code .
U hav engine code right now ?
if yes , can check it out easily
if no , the machine can Check "historical engine code "

i hav my own machine called : Launch X431. can check any codes u wanted .

i am sorry , i dont mean Alarm
i mean Immobiliser , that kept inside ur key
urs vios is wad year ?
first batch vios dun hav
2nd latest batch MACAM got immo

the disarm pen is Belong to cobra company , does Not consider as immobiliser

anyway , check engine code
i beloeve some sensor running out

suspect Cam / Crank timing sensors

use a computer of coz
but since u r user , u wont udnerstand what i mean

send to those workshop that hav engine diagnostic