Dock moves to monitor that's turned off - how do I stop it?

Let me start by saying I'm new to the Apple desktop ecosystem, been using an iPhone and iPad for many years, in October I purchased a MacBook Pro13 and after a very positive experience in initial video editing I purchased a Studio and have started to shift my video editing to the Mac as I continue to learn FCP. I've been using Windows based PCs since DOS 2.11 and Windows v1.0beta, had a computer service company for a few years and have built dozens of custom builds for customers and myself, so my computer skills are very high on the pole. Until I started on the Macs, the rules and names are different but the concepts are still the same. No I haven't and won't abandon my Windows PCs, there are some things I'm more comfortable doing on it and I have multiple software applications that work best for my business on the PC.

Sorry, I got off track a little. Here's my questions.

My Studio has 2 34" ultra wide monitors and a 55" Samsung TV connected. I do all my work on the 34's and use the 55 to preview the work in 4K before transmitting to my customer. The 55 is off about 90% of the time. When I startup the Studio the login and the Dock position themselves on the 55 even though it's turned off, and not on one of the 34s. How do I:

a) stop the dock from shifting around?

b) chose which monitor it appears on?

c) lock the dock onto a specific monitor?

d) stop the mouse from running onto the 55 when it's turned off?