What version of kde? I haven’t tried it, or read about it beyond the changelog, however the latest beta release says that it supports RDP to connect to plasma desktops which is quite an interesting development if it works the way it sounds like it does:
Remote Desktop system integration to allow RDP clients to connect to Plasma desktops, plus a new page in System Settings for configuring this
For the “from anywhere” component you could use a vpn, but if you’re looking for a simple solution with zero configuration than nomachine or rustdesk seem more appropriate. Just thought the RDP support was worth sharing.