“Percona Server for MySQL® is a free, fully compatible, enhanced and open source drop-in replacement for any MySQL database.” – https://www.percona.com/software/mys…percona-server
Finding a traditional Shared Hosting company offering MySQL 8 would be a long search and, potentially, fruitless.
This might be worth exploring: https://www.sqlclusters.com/pricing/
I only have experience with their sister company, VPS Mart, but I have been extremely happy with them.
Under Management Features, it specifically says that they support 8.0. These use Kubernetes with Ubuntu 18.04 LTS and Docker, so they are essentially a fully managed VPS.
That’s all that I can think of at the moment.