Not quite. When you are on your local network, and you have enabled “Screen Sharing” in the Sharing section of the General Preferences pane, that Mac will show up in the Finder sidebar of other Macs on the local network under “Sharing”. In Path Finder (which I use) it shows up under “Shared” with a distinctive screen sharing icon.
When you click on that machine’s name from another Mac, the Screen Sharing app will launch and you’ll be prompted to log in to the machine. Once you do so, you’ll see the other machine’s screen on the Mac you are using.
Screen Sharing is very useful for me, but it does have some quirks:
You are limited to the screen aspect ratio and resolution of the host machine. On my current iMac with a 5K Retina screen, it’s a little jarring to see how crude my late-2012 iMac’s screen appears.
There can be artifacts, such as the pointer leaving a “ghost trail” behind.
If the host machine goes into sleep mode, it can be difficult to wake up.
It can be confusing to know which machine you’re controlling, especially in regard to the Dock and Application Switcher.
All minor stuff compared to having access to apps that won’t run on my newer machines.
My older iMac runs on High Sierra; I do not use it for email or Internet access any more, and count on both its firewall and the very good one built into my router to protect it.
Having designed and produced a few books, and still working in graphic design on occasion, I can affirm that Affinity has filled in many of the gaps that opened up when Adobe decided to go subscription.
Publisher still has a long way to go to match the prepress capabilities of InDesign, though Publisher 2 has made advances. Serif is developing features deliberately and with a gimlet eye on their actual usefulness. InDesign had the kitchen sink thrown at it when it launched because (1) it had to carry virtually all the features of Aldus PageMaker, which Adobe swallowed up in order to kill and eat; and (2) it was in direct competition with QuarkXpress, which I still think was a horrible program that did its job well if you could stomach its interface.
Publisher 2 has added some features, but each one added has a cost in terms of programmer effort.
Since many other applications and services have added electronic signing to their repertoire, I don’t think Publisher is going to jump on that bandwagon any time soon.