Do I need Thrive Architect to use Thrive Optimize?

Yes, Thrive Architect is required to use Optimize.

WordPress Plugins

WordPress is almost infinitely extensible. With the help of WordPress plugins, more features can be added to your site. Mostly without major effort or programming.

Mein WordPress-Plugin Favoriten:

Yoast SEO (free & premium) The SEO Plugin.
AntiSpam Bee (free) helps very well against comment spam.
Enable Media Replace (free) replaces images in your library. Super handy when you need to replace images.
Lightweight Subscribe To Comments (free) notify your readers about new comments. This is how you keep your discussions active.
Site Kit von Google (free) Inserts the Google Analytics code into your blog and brings the stats into your dashboard.
Yoast Duplicate Post (free) Copy posts and pages. If you use templates, you can duplicate them with the plugin and continue writing right away.
WP Rocket (premium) The best plugin for caching and performance optimization. Unfortunately there is no free version of it.
Link Whisper (premium) helps you to create internal links. I still wouldn’t use the automation though. Is super helpful to find suitable posts to link.
Ad Inserter (free & premium) is super handy if you want to automatically display ads or banners on your website.
Polylang (free & premium) is my favorite plugin for multilingual websites. Most of the time I even get by with the free variant.
Pretty Links (free & premium) you should take a look at if you do affiliate marketing.
Reusable Blocks Extended (free) Since I’ve been using the Gutenberg editor, this is one of my favorite plugins. It gives you a new menu called Blocks where you can manage all your reusable blocks.
TablePress (free & premium) I need when the Gutenberg table block is no longer sufficient.
Simple History (free) is super handy when several authors or even admins work on a blog. So you can see who has done what.

I have this collection of WordPress plugins active on almost every blog. For customer projects, I usually get by with much less.

Plugins don’t have to slow down your blog, but they can. However, every plugin is a new potential security hole, so I always try to use as few extensions as possible.