This search turned up the following links:

• Aurora - A LaTeX Plugin for Microsoft Word
• Linear format equations using UnicodeMath and LaTeX in Word - Microsoft Support
• GitHub - rylandev/WordxTex: A Latex addin for word
• https://https://www.nature.com/artic...s/latexinword/
• Craft beautiful equations in Word with LaTeX

"Are there any Latex add-ons for MS Word?"

Proposes "Aurora”. Good hint! I used a paid/licensed “Aurora” for many years (excellent software!). But: When now re-installing my OS, and therefore also re-installing, it refuses to register & moans: "I could not connect to the validation server".

Is there a contact-address / -person known of elevatorlady.ca?

Greetings from Kochel in Bavaria, Wolf