I doubt you would need any tips, also right now Bookworm is closer to upstream than Ubuntu, so it’s better fit for gaming sans some niche missing package scenarios that won’t matter if you heavily rely on flatpaks.
The only major thing Ubuntu has over Debian is the normie friendly graphical , but it’s not great so /shrug .
Also Canonical is not going to pull the plug, that’s one thing you don’t really have to worry about, unless they sell the company.
I don’t think I can go back to Nautilus after using Dolphin for so long, even if the search is far better.