For Oracle Linux and RHEL...

sudo yum install -y https://repo.percona.com/yum/percona-release-latest.noarch.rpm

For Ubuntu...

sudo apt update

sudo apt install curl

cd /tmp

curl -0 https://repo.percona.com/apt/percona-release_latest.generic_all.deb

sudo apt install gnupg2 lsb-release ./percona-release_latest.generic_all.db

sudo apt update

sudo dnf module disable mysql

and you may need to do this...

sudo dnf install compat-openssl10

To populate your local yum repository you could use something like this...
Note how you can filter to show only files suitable for a specified point release by changing the URL appropriately...

rm index.html

wget http://repo.percona.com/pdps-8.0.28/yum/release/8.0/RPMS/x86_64/

for i in `cat index.html | grep rpm| cut -f2 -d'"' | grep -v debuginfo | grep -v debugsource`

do

        rm -rf $i

        wget http://repo.percona.com/pdps-8.0.28/yum/release/8.0/RPMS/x86_64/$i

done 

sudo dnf install percona-server-server

You can revisit this properly later but, if you have already created any files or subdirectories under /var/lib/mysql then, at a minimum, create a subdirectory called /var/lib/mysql/data and set the datadir configuration variable in /etc/my.cnf to point to it. MySQL will not start if the datadir is not empty.

sudo mkdir -p  /var/lib/mysql/data

sudo vi /etc/my.cnf

datadir=/var/lib/mysql/data

Find out the initial password...

sudo grep 'temporary password' /var/log/mysqld.log

Use it to login...

mysql -u root -p

Change the password (be sure to store it somewhere securely)...

ALTER USER 'root'@'localhost' IDENTIFIED BY RANDOM PASSWORD;