Problems during system reset from old time machine backup
I just managed to get a used logic board for my old MacBook air which I had not used over two years. I have a 256 GB internal SSD with osx Mojave on it. When I switch on the system it showed a white screen with a grey folder+ question mark. Using a bootable external USB drive it could go up to DiskUtility showing all the drives . I repaired all the drives. But Recovery server could not be contacted.
I see two drives: DPM HD and Time machine (TM)
Selected TM back up (a full back up exists from Nov. 30, 2020)
I see the message 'You cant restore this backup since this Mac's firmware does not support from APFS'
Tried to Install mac osx. That led to system hanging with the rainbow wheel.
Tried to go for the internet recovery but got the message that the old version of Mojave will not work because of some later updates.
Then tried to go through the terminal rout with erasing the container and reloading osx. No success here since the key 'r' is not working. That is very much needed.
Apparently three of the keys 'r', '4' and ']' are not working. Cleaned all the three keys.But there is no success. Can I use an external keyboard at this point?
Can not do PRAM/NVRM reset since 'r ' key is not working. I will sincerely appreciate any suggestion to revive the system. Thank you in advance.
Is this a good question?