Agreed. I am definitely also distracted by the red underlines but also am sometimes distracted by the uneasy feeling of having spellcheck disabled.
Being able to quickly toggle it on then off would give some peace of mind when working on a note that I fear may end up never getting spellchecked again before I funnel some of the text into other software that does not have spellchecking.
As a side note, you may appreciate my request of being able to ignore misspellings like in some other software. Here’s a link: Option to ignore misspelling
Thanks.