critical error

Hi ,
This problem gets me frequently.
I get a fatal error message and the PHP version is changed from 7.4 to 7.0.33.
I solved the problem by changing the version of PHP to 7.4 in htaccess.
The error message I get from WordPress is:

Welcome!
Because a feature is included in WordPress 5.2 that detects when a theme or plugin causes a critical error on your site, you are automatically notified by email.
In this case, WordPress has detected an error with one of your plugins, WooCommerce.
First, visit your site ( https://istawred.com/ ) and check for any visible issues. Next, visit the page where the error was detected ( https://istawred.com/wp-admin/ ) and check for any visible problems.
When asking for help with this problem, you may be asked for some of the following information:
WordPress 6.1 version
Current theme: Woodmart Child (1.0.0)
Current plugin: WooCommerce (version 7.1.0)
PHP version 7.0.33

Error details
===== ==================
An E_PARSE error occurred due to line 29 in the file /home/u660785310/domains/ istawred.com/public_html/wp-content/plugins/woocommerce/vendor/symfony/polyfill-php80/bootstrap.php. error message: syntax error, unexpected '?', expecting variable (T_VARIABLE)

The page I need help with: [log in to see the link]