Simplest form is to lock the mu-pugin folder (if you have FTP rights). But in reality, Switching hosts won't help in the long run and neither will plugins that fight the bloatware MU-plugins. To answer your question, don't move to another WP-host. They're all the same, with just different problems... it drove me nut when I was 14. Instead, you should look into running your own server, the way you want it. There are many resources on youtube that have helped me throughout the years.
I run my own WP site(s), each with a dedicated Ubuntu server, 1GB of RAM, 1Tb both up/down, 25gb of storage, free SSL, firewalls AND most important I do backups, and this all costs me $5-6/month.
Interestingly, just recently one of my servers got this bloatware. In my case, my firewall decided to have a mind of its own, by doing so it installed bloatware and partially blamed WordPress. Why? It didn't believe it was protected by SSL. I know this since I checked on on the logs.