My site is down due to site code

Hello
I'm using Generate Press (I think it is Merch Theme).

My haticexinterior.com is down. I can't login both regular Wordpress login page and even from c-panel/Softaculous.
It says;
'There has been a critical error on this website.'

Only my landing/front page is opening. All other menu (about, contact) blog categories and pages are not opening.These are all in 500 error in google search console.

When I wrote my hosting provider, they said that:

The error you're seeing is a site-code issue and not server-side, as such, this would typically be something you reach out to your developer in regards to.

If you check your error_log file, you'll find the issue is as follows:

[15-Jun-2022 05:11:13 UTC] PHP Fatal error: Uncaught Error: Class 'WPO_Page_Cache' not found in /home/haticexi/public_html/wp-content/plugins/wp-optimize/cache/file-based-page-cache-functions.php:813
Stack trace:
#0 /home/haticexi/public_html/wp-content/plugins/wp-optimize/cache/file-based-page-cache-functions.php(889): wpo_get_conditional_tags_exceptions()
#1 /home/haticexi/public_html/wp-content/plugins/wp-optimize/cache/file-based-page-cache.php(31): wpo_url_in_conditional_tags_exceptions()
#2 /home/haticexi/public_html/wp-content/advanced-cache.php(58): include_once('/home/haticexi/...')
#3 /home/haticexi/public_html/wp-settings.php(95): include('/home/haticexi/...')
#4 /home/haticexi/public_html/wp-config.php(79): require_once('/home/haticexi/...')
#5 /home/haticexi/public_html/wp-load.php(50): require_once('/home/haticexi/...')
#6 /home/haticexi/public_html/wp-blog-header.php(13): require_once('/home/haticexi/...')
#7 /home/haticexi/public_html/index.php(17): require('/home/haticexi/...')
#8 {main}
thrown in /home/haticexi/public_html/wp-content/plugins/wp-optimize/cache/file-based-page-cache-functions.php on line 813
For your shop subdomain the error is as follows:

[15-Jun-2022 04:52:35 UTC] [ERROR] : WPO_ADVANCED_CACHE constant is not present in advanced-cache.php
I can see your main site no longer has that plugin and as such is working, this is the same for your subdomain.

Will you help me how to solve my problem,

Kind regards,
Dr Hatice Ozhisar