Safari changed all my bookmarks - Can I change them back?

I've always run my iMac M1 from an external Thunderbolt drive. Yesterday, I installed a clean system on the internal drive. I had to, because when I use Logic Pro on my regular system, there is a delay introduced when I play my MIDI keyboard. I use my computer for a lot of things, and I think there are just too many devices on the USB bus. Installing a clean system just for songwriting (and video editing) seems to have done the trick, but then later I switched back to my regular system and opened Safari. It was fine at first, but as soon as I tried to bookmark a page, all my bookmarks from this system were replaced by the ones from the new system. I looked for an answer to this but so far I haven't found one. I do have the system backed up with Time Machine. Is that what it's going to take? And if I restore these, will they just switch again after the next time I try to play my keyboard?