Honestly, I would wait it out. I'm one week into migrating to 2.4.3 from 2.4.2-p1 and there are ton of issues, especially with the plugins from vendors.
Just upgrade to 2.4.2-p2 and give it a month or two.
And yes, you can upgrade and its not super difficult to do so.
composer remove magento/product-community-edition --no-update
composer require magento/product-community-edition 2.4.3 --no-update
Remove anything in your replace section and then
rm -rf var/generation var/view_preprocessed/ pub/static/frontend generated/code
php -dmemory_limit=6G bin/magento setup:di:compile
php -dmemory_limit=6G bin/magento setup:static-content:deploy -f
php -dmemory_limit=6G bin/magento cache:flush
FYI do not update your Production server without testing the upgrade on DEV. That would be a disaster! There are just too many things that could go wrong and too many bugs that are present even in a newly released version.