it is like moving from window to linux desktop . it take time to adjust to new environment.
modern linux desktop can be as good as window desktop these days. there is also mac OS but it is mostly use by apple / iphone fan..
if one had the time to learn about system administration, then unmanaged vps will be ideal but do not use it on production server. maybe start as a hobby and then move on. the last resort is definitely getting an experience tech support company to do all the chore .
second domain can be hook to your main domain account. files are keep in a subdirectory. maindomain.com/seconddom
visitor see the same content on secondomain.com and maindomain.com/seconddom