unlock bootloader and following root the device

[Co01ler]

Hello there,

I've read many topics and watched many videos before bothering you guys here so I'm sorry if my question is too stupid or inappropriate, but I'm lost and really want get this done and play with my phone.. I'm new to android at all, coming from jailbroken iOS which I don't like that much these days, so I wanted to give android a try. First of all I'm using:

ubuntu 18.04
Nokia 7.1 - Android 10
model: TA-T1100
Build number: 00WW_4_08B_SP01

what I did:
1. downloaded fastboot and adb tools to my system by typing this in terminal

apt-get install android-tools-fastboot

apt-get install android-tools-adb

everything works fine, so next step for me was unlocking developer mode on my phone by taping on build number in about phone settings serval times after unlocking developer mode I allowed USB debugging in developer options.

now when I type this in my terminal

adb devices

Now after allowing debugging I can see my phone listed here

when I try type

fastboot devices

nothing happens

same with

fastboot reboot

terminal keep waiting for the device to connect but nothing happens

but when I try

adb reboot bootloader

my phone restarts and here comes the trouble... android-one logo appears with tiny text in the left corner which says "download mode" I gave it good 20 minutes but nothing else happens, noting else appears only what I can do is restart my phone by long pressing "turn on" button and boot normally

so if anyone can help me get thru this and actually root my phone I'd be grateful

have a nice day everyone