In general, according to Support Policy we can help only if we have access to site URL. Not remote localhost.
Please:
- Write full template name
- Record video with all problems, and share link to it
About "menu would appear too small to read/navigate " you can change font size from Typography settings or by custom CSS if you like that method.
About "The off-canvas menu 3 bars buttons would appear off the header" - have you used Predefined header or custom header?? if 2nd answer, you can correct that by using correct columns width size. I created a video about that on youtube some time ago.