Hello !
To your 2nd problem:
Try the following code in the affected template style in the "Custom CSS":

.j51 inline icon svg {

color: #e61111;

}

You can then adjust the color: white e.g.: #fff

No difference. The caret is there - but it's a faint grey.

A link to your site is a better way to solve this.

a "-" was missing
Try the code:

.j51-inline-icon svg  {

color: #e61111;

}

It seems to be affecting it but not fixed. Here's the home page of one site: https://vintagefilmfestival.com/ I changed the colour to #fff

It's now fixed. It was the opacity on .parent-indicator that was too low - in nexus.css line 1128, opacity is 0.35.
This custom code fixed it:
.parent-indicator {
opacity: 1.0 !important;
}
To trouble shoot I isolated code for that item showing that the caret was defined by both classes j51-inline-icon and parent-indicator. Then I searched css files for these classes. Once I saw the opacity style, I could see the problem. Thanks eumel7 for the pointer.

Further to the issue about the missing Print/Email icons. I came across an item on the Joomla Forum. It seems that they were removed with Joomla 4. So it's not a template issue. The suggested way to print page contents without the header and columns is to select the wanted content and then print - e.g. right click and print. That is, use the browser capability.

Nice. Thank you for the update and for sharing your solution

Ciaran