I am a safari user and don’t keep _that_ many tabs. I experienced tab reloading, which I didn’t mind. But even after a week of use I found I benefitted from rebooting to clear out memory.
I'm a little surprised so much of your 8gb went away using Safari if you don't keep too much open. Safari is generally great, but I've had to deal with abysmally large Google Sheets and had it reload every time I switched away even though it was the only window/tab open--Firefox wasn't too much better, it would constantly recalculate formulas. I feel like I got that behavior in Safari one or two other times with heavy SPA, but normally it uses much less battery and seems to use much less RAM than Firefox or Chrome.
I also haven't seen much of a need at all for regular rebooting. Looking back it seems like I'll reboot my laptop every 2-3 weeks, usually for an app that has a kernel driver, to boot into Windows, or to troubleshoot an egregious problem like my sound or bluetooth breaking. I've never done it for RAM, but I have closed browsers to save battery/RAM.
I also haven't seen much of a need at all for regular rebooting. Looking back it seems like I'll reboot my laptop every 2-3 weeks, usually for an app that has a kernel driver, to boot into Windows, or to troubleshoot an egregious problem like my sound or bluetooth breaking. I've never done it for RAM, but I have closed browsers to save battery/RAM.