Tied everything to root swift, cant get past initial fastboot stage

hi all, sorry if this has beeen posted before but its bugging me as i spent literally 4-5 hours lastnight trying to sort it, i havee rooted 4-5 android phones in the past but im just having no luck with this one

i installed adb / fastboot minimal, enabled what needed to be enabled in developer options on the swift, booted the swift into fastboot mode, then when i run adb on my computer, the first command works 'fastboot oem unlock' but after that its constantly saying 'waiting for devices' whenever i try the next phase of commands ie. fastboot -i 0x2970 oem unlock-go etc it just wont detect the device at all in windows on adb, is there any suggestions anyone could throw out there before i end up sending it back and getting an alternative android phone thats easier to root? the only thing i can think off is its a usb driver issue? but i installed the gloogle usb drivers and it picks up the phone for file transfer etc so im not sure if this is the issue. many thanks!

I tried this but it still says 'waiting for any device' My initial command worked for fastboot oem unlock, but then I just couldnt do the following commands, and as a result whenever i tried to install a custom recovery / rom it gave me the error along the lines of 'unable to verify....'

edit: when i missed out the -i part, then said its already unlocked. however i still am not able to install supersu or the recovery as it still gives me the error 'signature verification failed'