Android

What apps require root that you want? I would highly advise against rooting if you can help it, because especially if you don't know what you're doing, there is very high potential to brick your device or open up security issues. I would recommend learning what root actually means and what it entails, and learning everything that happens when you root so you can decide for yourself if that's something that is necessary. Rooting modern hardware just to run an app is not really all that important nowadays. You might as well buy an android that has a custom OS already installed centered around privacy if that's your thing.

Additionally, to actually answer your question, adb is not root. It is just a development bridge that lets your PC talk to your phone, so you can push apps or do other development related stuff. It just happens to be a part of the toolset when rooting.

adb = connect your phone to your pc and send commands to it. Can do things that aren't included in the Android user interface, but can't touch the core system or give you extra rights. Necessary for the Universal Android Debloater and flashing custom ROMs.
root (most common method is Magisk) = gives you access to functions that are normally off limits. Its utility is overestimated if you just want to use your phone as a phone, but it lets you use it for purposes it wasn't designed for. Not necessary for degoogling, microG installation or flashing custom ROMS.
unlocking bootloader = necessary for rooting, flashing a custom ROM or replacing Google Play Services with microG. Degoogling without a custom ROM and microG is possible, but a pain in the ass and limited in functionality. You want this.
custom boot loader (most common is TWRP) = necessary for flashing custom ROMS and installing microG.

If your phone is supported by TWRP or a custom ROM (look at LineageOS first), installing that is the easiest way to completely degoogle.
If it isn't, then you can still root it, remove Google apps with adb and use Netguard to keep any Google apps you still need from phoning home. But getting push messages, location and speech recognition/synthesis to work in your apps is a crapshoot. You will probably be limited to the functionality of open source apps that don't depend on Google services.

If you're considering rooting, I'd say don't. Rooting is like blowing a hole in the wall of a castle. It breaks the Android security model. A rooted device is insecure and cannot be made secure no matter how many Magisk modules you flash. Do not root a device you do anything important on.

My recent interest in rooting is purely because I have some foss apps that require root for me to use the full capabilities that I want.

Example? I personally just deleted unnecessary apps with adb and went on. Google Play services are still running but that is really it. After rooting getting updates will be difficult so you will want a custom ROM. Decide if that is what you want to do.