I changed to Https without a plugin installed. Can’t access admin panel. Help!

Thanks for your suggestion, but please can you be more specific? I tried to add those lines to htaccess, but still doesn’t work. I can not access my admin page.

Thank you (@keithdriscoll)! I tried your first step with both solutions and it didn’t work. So I couldn’t make activation of any plugin because I couldn’t access my admin page (Error 500 – could not access the page). I could upload the plugins through FTP, but no activation possible.
Finally, I solved the problem and come back at HTTP by using settings from phpMyAdmin which I could access through CPanel. In My Options, we can find those 2 paths from the original settings. I modified them back to HTTP instead of HTTPS and everything started to work again, but the options from my website still didn’t work. So, I did only a save of Permalinks to update the links between pages and DONE.
I used information from
https://kinsta.com/knowledgebase/change-wordpress-url/