Erros during polls upgrade

Today I see this and update polls page. I just tried it but always fail (we are running 20.0.6 version):

Doctrine\DBAL\Exception\DriverException: An exception occurred while executing ‘CREATE UNIQUE INDEX UNIQ_options ON oc_polls_options (poll_id, poll_option_text, timestamp)’: SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 767 bytes

I see some solutions at forum like this:
sudo -u www-data php occ app:disable polls
sudo -u www-data php occ maintenance:mode --off

Is this correct?

regards, I

More info:
mariadb is 10.1.38

I have been reading this too:
But seems not to be the right way for this DB versión.
regards, I