In the Finder, go to the Finder menu, to Preferences, to Sidebar. There you can configure WHAT items show in the side bar. Then open a Finder window, and drag them up and down, into the order you prefer them in, to set HOW they show up.
As for RW6 simply not being visible, that should not happen. I've done lots of Mac OS updates for many, many years, and have never seen nor previously heard of an app simply not being visible. Now, if it isn't showing up in a Spotlight search, it may be that Spotlight hasn't finished re-indexing the drive after the OS upgrade. That can take a bit of time at first.
I teach post-production for broadcast and film mostly, and there are a series of regular maintenance steps I teach for everyone using their Mac to make a living with.
- Have an automated backup in place. TimeMachine is a nice consumer level solution, but use something more robust and professional like Carbon Copy Cloner. Automate this to happen at night when you're not using the Mac for work.
- Verify all drives have at least 15% of total capacity left as free space, the more free space the better. Less than that WILL cause issues, and the symptoms may not fit any textbook category.
- Run Disk Utility's First Aid on all drives.
- Run Disk Warrior to repair the directories on ALL drives. Single most common cause of drives seemly crashing and loosing all data are corrupted drive directories, not physical damage. If you run Disk Warrior, and it has a problem with a drive, REPLACE that drive ASAP!
- A minor update isn't much, but a major number upgrade can be a gamble. Always place a backup copy of the application you make a living with somewhere safe off of the system drive before running a major app upgrade. And backup all your project files and data. THEN upgrade the app. Worst case, you bring back the pre-upgrade version and lose only an hour or so of time.
- When upgrading an OS, immediately do a manual FULL, BOOTABLE backup of your system drive. If you need to have explained to you why, then we need to sit down over a whiskey and educate you about how computers work.
I'm actually retired IT engineer and did media production on the side. about 20 years ago I dropped IT work and started doing media production full-time. I've done lots of consulting for broadcast and other media production outlets. I've seen a lot of scenarios where data gets lost, drives crash, systems blow up, or warp into another dimension of space and/or time. But doing the above maintenance procedures, I've had many, many, many clients and students (as well as my own studio's Macs) run trouble free for years and years, even through OS upgrades.
Personal hint; when upgrading the OS, do it at the end of the day. Once done, do a cold boot, then let the computer set undisturbed overnight. Usually you can find performance back to normal (if not better). And be wary of upping the OS on an old computer (3-4 years or older), as older computers that don't have the newer chip sets may not be as efficient with a newer OS.