Thank you for reaching out with your question in the Community, FPCNS.

Desiring an answer is a positive feeling, and I am here to provide you with the information regarding your concern.

You can use incognito mode anytime. If you use Incognito isn't to speed up the program response behavior, it's to confirm if your regular browser has cached too many files, which can possibly cause the program to behave unexpectedly. 

When using incognito mode, please remember to verify your account each time you log in. 

You can also check this article on troubleshooting browser problems in QuickBooks Online. 

Please let me know if you have another questions regarding with your QuickBooks concern, Community is always here to answer. Stay safe!