The other day a posting else where caused me to check my custom menus and found them broken for Google Links.
Just sharing what I found that works - repeating actually - and something new ...
Had a menu for Google Help - docs, sheets, etc. that broke - actually linked to old tutorials ... now fixed:
Links used ? in them ... found fix else where in these forums:
replaced ? with ?
-Docs | https://support.google.com/a/users/topic/11525708?hl=en&ref_topic=9247638" target="new
-Drive | https://support.google.com/a/users/topic/11505857?hl=en&ref_topic=9247638" target="new
-Meet | https://support.google.com/a/users/topic/11525626?hl=en&ref_topic=9247638" target="new
-Sheets | https://support.google.com/a/users/topic/11506529?hl=en&ref_topic=9247638" target="new
-Slides | https://support.google.com/a/users/topic/11524938?hl=en&ref_topic=9247638" target="new
-Drive | https://support.google.com/a/users/topic/11505857?hl=en&ref_topic=9247638" target="new
-Meet | https://support.google.com/a/users/topic/11525626?hl=en&ref_topic=9247638" target="new
-Sheets | https://support.google.com/a/users/topic/11506529?hl=en&ref_topic=9247638" target="new
-Slides | https://support.google.com/a/users/topic/11524938?hl=en&ref_topic=9247638" target="new
Also something new on the Google end ... they now have 'shortcuts' ...
OLD:
New shortcuts ... work! Most be logged onto Google to work flawlessly.
-Doc|https://doc.new" target=new"
-Sheet|https://sheet.new" target=new"
-Slides|https://slides.new" target=new"
-Form|https://form.new" target=new"
-Sheet|https://sheet.new" target=new"
-Slides|https://slides.new" target=new"
-Form|https://form.new" target=new"
Now if I could find a way to point to certain folders so that all the students work would be in a folder shared with teacher. Like Moodle, Google keeps changing ... just gotta keep digging and paying attention to changes! 
Anyhoo ... thought I'd share ...
'SoS', Ken