I don't know if it would help or improve things better for you, but for years I have been using the Finder menu ClipMenu that I find invaluable for multi-clip clippings and pasting, and using it to Paste whatever I had copied seems to work well with everything I have ever tried:I just discovered a solution to an accessibility issue I was having ...
Say something online ... A Tweet, some copy here and I want to copy it.
In accessibility mode, (All the "inverts!") it is generally not readable without some work ... it's either invisible in Mail or in Word it has a box around it and thus everything has needs to be changed ... formatting and spacing and yada yada
But maybe it's not exactly what you were after, but I couldn't work without it.
As for the Mac OS Accessibility, I use some of it, especially their Dictation, but unfortunately, the Google Chrome extension Voice In works much better and requires a small annual fee, but only works in Chrome applications, but I rely on them both due to the severe rheumatoid arthritis and gout that I have in my hands which makes it hard to type.
Here's hoping your new Mac works out for you...