www.gsmarena.com
ADB is a really useful utility, but it's also not going to be able to do everything and anything you want. I'm not saying rooting will be able to solve your problem either, it's also a way to be able to do more intensive, low-level tweaking. Rooting also involves a lot increased risk and usage problems. It's not a magic fix that some claim it is, do it to specific reasons. In your case, rooting your phone would allow you to try to clean up bloat locally, using native Android uitilies on your phone. ADB relies upon remotely accessing your phone. But again, some models are difficult to root.
Also, switching ROMs is not a requirement after rooting. Basically you're rooting the installed Android OS, just changing its permission levels. Continue using your rooted phone with its stock ROM or go through the added process of flashing a third-party ROM. That's your choice.
When your phone is rooted, this allows you access to the operating system and base file structure. In its normal status, unrooted, there's always a disctinction between root status and a general user. It's not like Windows as so many people mistakenly believe. With Windows you can just give a give a general user Administrative privileges (as long as you know the Admin password). With Android however, that kind of easy access isn't as easy to bypass.
Have you looked through some of postings at XDA Developers on your model for tips:
The Xiaomi Redmi 6A is a 5.45" phone with a 720x1440p resolution display. The Helio A22 is paired with 32GB of RAM and 16GB of storage. The main camera is 13MP and the selfie camera is 5MP. The battery has a 3000mAh capacity.
xdaforums.com
Something lhis MiUI Debloater might help:
MIUI 12.0.2.0 Debloater patch Version: beta 2 This patch is designed to remove garbage from the latest official version of MIUI for Redmi 6 and 6A. After the removal of Chinese applications, the smartphone becomes more usable. Installation: 1)...
xdaforums.com
This being your daily usage phone, be extra careful.