This evening, I spent my Friday evening after work porting all my browser tabs into Zen browser, which is a Firefox-like browser. It didn't work, it would hang on all my stock tabs, so today, Saturday I installed Brave browser and set it up to work a lot like Sidekick. You can group tabs, just like Sidekick. You can also pin your main Applications, so they are available all the time. Brave browser uses a lot fewer system resources compared to Zen browser.

Received a refund quickly from AppSumo. I Wish Sidekick would have just raised more money again by coming back to AppSumo, but oh well. I cannot control everything. If someone knows a better browser to use, which is up to date, please let me know. But the Brave browser seems to be working well for the brief time I have been using it. I have an M1 Mac with 16GB RAM.