I feel I'm eating crow on this because I have absolutely sworn to Extensis Suitcase since the Mac OS days when Suitcase shipped to you on a floppy disk. Until about two months ago, I happily used Suitcase Fusion. But then I got a new laptop. I realized that my 5-year-old iMac with Adobe CC 2019 apps launched and operated faster on that machine than my new laptop with faster components. The only difference was that I had no Suitcase Fusion installed at the office.
I did some testing of virtually every app I could find. Most all of them suck as a serious font manager in comparison to Suitcase Fusion (that includes Font Agent and FontExplorer). One app stuck with me, and I've been using it ever since. It's a "middle of the road" app, sandwiched between Apple's FontBook and Suitcase Fusion.
RightFont 5 looks great, allows you to create collections, auto-activates in Adobe CC apps as well as Affinity & Quark apps, and most importantly; it runs much the same as Suitcase, except it doesn't appear (after a few months of use) to slow down Adobe apps (particularly InDesign, which Suitcase was absolutely killing as of late).
It's not a perfect app. For starters, you have to keep it running in the Dock all the time. This is more of an annoyance than a problem. It's also lacking a lot of nice features that Suitcase had. But, RightFont 5 is only $40, where most other professional font managers are $100 or more. And it does have some nice features (like font syncing via iCloud, Dropbox, GoogleDocs, etc.).
It's definitely worth looking at if you need more than Apple's FontBook but find Extensis Suitcase too much.