What to do with the site sagging in positions?

Question

Search Engine Optimization

Hello. The question is. There was a site with the following parameters: -
Attendance 1500 people / day - HTTP
protocol
- Engine No. 1
- Functionality, conditionally 100% - Non-
adaptive design
became like this, after transferring to another engine and https protocol
- Attendance 100 people / day
- HTTPs protocol
- Engine №2
- Functionality, conditionally 50%
- Responsive design
1 year has passed, traffic after the transfer to Https has not returned to its previous level.
Apparently it was translated crookedly, perhaps there is little functionality, but it should not have sagged so much.
It was written to Plato, Plato unsubscribed as standard, work a Negro.
The question is, what to do next - continue to hang on the second option and work like a black (or maybe I'm in filters, from an unsuccessful
translation ...) or spit and return to the old engine and http, transferring new content to the old engine?
Dear pros, what do you think will happen if, after 1 year on the new engine, https is transferred to the old http, how will the search engines behave in this case
? Any thoughts would be a help, thanks.

Answer 1

a year is too much, everything has flown away already

Answer 2

Or maybe even change the domain, while it seems nothing to lose.

Answer 3

It's too late to think. If you return to the old engine, remove the adaptive and https, then most likely your attendance will generally drop to 0.
Well, it’s also interesting, have you really not done anything on the site in a year to increase traffic, that it has remained at the same level? In a year, it was even possible to finish an unsuccessfully translated site up to 1500 and overtake it.

Answer 4

It was written to Plato, Plato unsubscribed as standard, work a Negro.

What promotional activities have been carried out?
Usually, after switching to https and traffic drops by 30-40% and after 3-4 weeks it reaches 80-90% of normal traffic.
You always need to take care of the content of the resource, sites are made not for search, but for people.